Leetcode Solutions with JavaScript or C++

Update time: Wed Oct 18 2017 19:49:19 GMT+0800 (CST)

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Tag:hash-table

ID	Title	Difficulty	Acceptance	Tags
116	Populating Next Right Pointers in Each Node	Medium	36.9%	TreeDepth-first Search
10	Regular Expression Matching	Hard	24.2%	StringDynamic ProgrammingBacktracking
1	Two Sum	Easy	35.6%	ArrayHash Table
4	Median of Two Sorted Arrays	Hard	22.1%	ArrayBinary SearchDivide and Conquer
3	Longest Substring Without Repeating Characters	Medium	24.4%	Hash TableTwo PointersString
2	Add Two Numbers	Medium	28.0%	Linked ListMath
7	Reverse Integer	Easy	24.5%	Math
8	String to Integer (atoi)	Medium	14.0%	MathString
9	Palindrome Number	Easy	35.5%	Math
10	Regular Expression Matching	Hard	24.2%	StringDynamic ProgrammingBacktracking
4	Median of Two Sorted Arrays	Hard	22.1%	ArrayBinary SearchDivide and Conquer
1	Two Sum	Easy	35.6%	ArrayHash Table
3	Longest Substring Without Repeating Characters	Medium	24.4%	Hash TableTwo PointersString
107	Binary Tree Level Order Traversal II	Easy	40.8%	TreeBreadth-first Search
554	Brick Wall	Medium	45.7%	Hash Table
525	Contiguous Array	Medium	40.5%	Hash Table
508	Most Frequent Subtree Sum	Medium	52.3%	Hash TableTree
500	Keyboard Row	Easy	59.7%	Hash Table
463	Island Perimeter	Easy	57.3%	Hash Table
454	4Sum II	Medium	47.2%	Hash TableBinary Search
451	Sort Characters By Frequency	Medium	51.1%	Hash TableHeap
447	Number of Boomerangs	Easy	45.4%	Hash Table
438	Find All Anagrams in a String	Easy	33.7%	Hash Table
409	Longest Palindrome	Easy	45.4%	Hash Table
389	Find the Difference	Easy	50.9%	Hash TableBit Manipulation
381	Insert Delete GetRandom O(1) - Duplicates allowed	Hard	29.0%	ArrayHash TableDesign
380	Insert Delete GetRandom O(1)	Medium	39.3%	ArrayHash TableDesign
359	Logger Rate Limiter	Easy	59.9%	Hash TableDesign
358	Rearrange String k Distance Apart	Hard	31.6%	Hash TableHeapGreedy
356	Line Reflection	Medium	30.1%	Hash TableMath
355	Design Twitter	Medium	25.6%	Hash TableHeapDesign
350	Intersection of Two Arrays II	Easy	44.7%	Hash TableTwo PointersBinary SearchSort
349	Intersection of Two Arrays	Easy	47.5%	Hash TableTwo PointersBinary SearchSort
347	Top K Frequent Elements	Medium	48.5%	Hash TableHeap
340	Longest Substring with At Most K Distinct Characters	Hard	39.0%	Hash TableString
336	Palindrome Pairs	Hard	26.4%	Hash TableStringTrie
325	Maximum Size Subarray Sum Equals k	Medium	42.8%	Hash Table
314	Binary Tree Vertical Order Traversal	Medium	37.1%	Hash Table
311	Sparse Matrix Multiplication	Medium	51.3%	Hash Table
299	Bulls and Cows	Medium	35.2%	Hash Table
290	Word Pattern	Easy	33.2%	Hash Table
288	Unique Word Abbreviation	Medium	17.0%	Hash TableDesign
274	H-Index	Medium	33.4%	Hash TableSort
266	Palindrome Permutation	Easy	57.3%	Hash Table
249	Group Shifted Strings	Medium	42.2%	Hash TableString
246	Strobogrammatic Number	Easy	40.0%	Hash TableMath
244	Shortest Word Distance II	Medium	38.9%	Hash TableDesign
242	Valid Anagram	Easy	46.7%	Hash TableSort
219	Contains Duplicate II	Easy	32.6%	ArrayHash Table
217	Contains Duplicate	Easy	46.1%	ArrayHash Table
205	Isomorphic Strings	Easy	34.1%	Hash Table
204	Count Primes	Easy	26.7%	Hash TableMath
202	Happy Number	Easy	40.9%	Hash TableMath
187	Repeated DNA Sequences	Medium	32.0%	Hash TableBit Manipulation
170	Two Sum III - Data structure design	Easy	25.0%	Hash TableDesign
166	Fraction to Recurring Decimal	Medium	17.7%	Hash TableMath
159	Longest Substring with At Most Two Distinct Characters	Hard	41.6%	Hash TableTwo PointersString
149	Max Points on a Line	Hard	15.3%	Hash TableMath
138	Copy List with Random Pointer	Medium	26.1%	Hash TableLinked List
136	Single Number	Easy	54.8%	Hash TableBit Manipulation
94	Binary Tree Inorder Traversal	Medium	47.4%	Hash TableStackTree
85	Maximal Rectangle	Hard	28.5%	ArrayHash TableDynamic ProgrammingStack
76	Minimum Window Substring	Hard	25.9%	Hash TableTwo PointersString
49	Group Anagrams	Medium	35.9%	Hash TableString
37	Sudoku Solver	Hard	30.8%	Hash TableBacktracking
36	Valid Sudoku	Medium	36.3%	Hash Table
30	Substring with Concatenation of All Words	Hard	22.0%	Hash TableTwo PointersString
18	4Sum	Medium	27.0%	ArrayHash TableTwo Pointers
32	Longest Valid Parentheses	Hard	23.1%	StringDynamic Programming
44	Wildcard Matching	Hard	20.4%	StringDynamic ProgrammingBacktrackingGreedy
53	Maximum Subarray	Easy	39.8%	ArrayDivide and ConquerDynamic Programming
62	Unique Paths	Medium	41.7%	ArrayDynamic Programming
63	Unique Paths II	Medium	31.9%	ArrayDynamic Programming
64	Minimum Path Sum	Medium	38.9%	ArrayDynamic Programming
70	Climbing Stairs	Easy	40.3%	Dynamic Programming
460	LFU Cache	Hard	24.3%	Design
432	All O`one Data Structure	Hard	28.2%	Design
381	Insert Delete GetRandom O(1) - Duplicates allowed	Hard	29.0%	ArrayHash TableDesign
380	Insert Delete GetRandom O(1)	Medium	39.3%	ArrayHash TableDesign
379	Design Phone Directory	Medium	33.6%	Linked ListDesign
362	Design Hit Counter	Medium	54.3%	Design
359	Logger Rate Limiter	Easy	59.9%	Hash TableDesign
355	Design Twitter	Medium	25.6%	Hash TableHeapDesign
353	Design Snake Game	Medium	26.7%	DesignQueue
348	Design Tic-Tac-Toe	Medium	45.9%	Design
346	Moving Average from Data Stream	Easy	59.1%	DesignQueue
341	Flatten Nested List Iterator	Medium	42.1%	StackDesign
297	Serialize and Deserialize Binary Tree	Hard	33.8%	TreeDesign
295	Find Median from Data Stream	Hard	27.5%	HeapDesign
288	Unique Word Abbreviation	Medium	17.0%	Hash TableDesign
284	Peeking Iterator	Medium	35.5%	Design
281	Zigzag Iterator	Medium	51.1%	Design
251	Flatten 2D Vector	Medium	40.8%	Design
244	Shortest Word Distance II	Medium	38.9%	Hash TableDesign
232	Implement Queue using Stacks	Easy	37.2%	StackDesign
225	Implement Stack using Queues	Easy	33.3%	StackDesign
211	Add and Search Word - Data structure design	Medium	23.7%	BacktrackingDesignTrie
208	Implement Trie (Prefix Tree)	Medium	29.1%	DesignTrie
173	Binary Search Tree Iterator	Medium	42.0%	StackTreeDesign
170	Two Sum III - Data structure design	Easy	25.0%	Hash TableDesign
155	Min Stack	Easy	29.3%	StackDesign
146	LRU Cache	Hard	18.4%	Design
72	Edit Distance	Hard	32.0%	StringDynamic Programming
85	Maximal Rectangle	Hard	28.5%	ArrayHash TableDynamic ProgrammingStack
87	Scramble String	Hard	29.4%	StringDynamic Programming
483	Smallest Good Base	Hard	33.3%	MathBinary Search
475	Heaters	Easy	29.6%	Binary Search
454	4Sum II	Medium	47.2%	Hash TableBinary Search
441	Arranging Coins	Easy	36.3%	MathBinary Search
436	Find Right Interval	Medium	41.4%	Binary Search
410	Split Array Largest Sum	Hard	38.2%	Binary SearchDynamic Programming
392	Is Subsequence	Medium	44.6%	Binary SearchDynamic ProgrammingGreedy
378	Kth Smallest Element in a Sorted Matrix	Medium	45.0%	Binary SearchHeap
374	Guess Number Higher or Lower	Easy	35.7%	Binary Search
367	Valid Perfect Square	Easy	38.4%	MathBinary Search
363	Max Sum of Rectangle No Larger Than K	Hard	33.3%	Binary SearchDynamic ProgrammingQueue
354	Russian Doll Envelopes	Hard	32.4%	Binary SearchDynamic Programming
350	Intersection of Two Arrays II	Easy	44.7%	Hash TableTwo PointersBinary SearchSort
349	Intersection of Two Arrays	Easy	47.5%	Hash TableTwo PointersBinary SearchSort
302	Smallest Rectangle Enclosing Black Pixels	Hard	45.7%	Binary Search
300	Longest Increasing Subsequence	Medium	38.6%	Binary SearchDynamic Programming
287	Find the Duplicate Number	Medium	43.7%	ArrayTwo PointersBinary Search
278	First Bad Version	Easy	25.6%	Binary Search
275	H-Index II	Medium	34.6%	Binary Search
270	Closest Binary Search Tree Value	Easy	39.9%	Binary SearchTree
240	Search a 2D Matrix II	Medium	38.7%	Binary SearchDivide and Conquer
230	Kth Smallest Element in a BST	Medium	44.2%	Binary SearchTree
222	Count Complete Tree Nodes	Medium	27.6%	Binary SearchTree
209	Minimum Size Subarray Sum	Medium	31.2%	ArrayTwo PointersBinary Search
174	Dungeon Game	Hard	23.9%	Binary SearchDynamic Programming
167	Two Sum II - Input array is sorted	Easy	47.1%	ArrayTwo PointersBinary Search
162	Find Peak Element	Medium	37.9%	ArrayBinary Search
154	Find Minimum in Rotated Sorted Array II	Hard	37.4%	ArrayBinary Search
153	Find Minimum in Rotated Sorted Array	Medium	40.2%	ArrayBinary Search
81	Search in Rotated Sorted Array II	Medium	32.7%	ArrayBinary Search
74	Search a 2D Matrix	Medium	34.9%	ArrayBinary Search
69	Sqrt(x)	Easy	28.0%	MathBinary Search
50	Pow(x, n)	Medium	26.1%	MathBinary Search
35	Search Insert Position	Easy	39.8%	ArrayBinary Search
34	Search for a Range	Medium	31.4%	ArrayBinary Search
33	Search in Rotated Sorted Array	Medium	32.1%	ArrayBinary Search
29	Divide Two Integers	Medium	15.9%	MathBinary Search
91	Decode Ways	Medium	19.9%	StringDynamic Programming
95	Unique Binary Search Trees II	Medium	31.7%	Dynamic ProgrammingTree
526	Beautiful Arrangement	Medium	54.5%	Backtracking
425	Word Squares	Hard	43.1%	BacktrackingTrie
411	Minimum Unique Word Abbreviation	Hard	33.0%	BacktrackingBit Manipulation
401	Binary Watch	Easy	44.8%	BacktrackingBit Manipulation
357	Count Numbers with Unique Digits	Medium	46.1%	MathDynamic ProgrammingBacktracking
351	Android Unlock Patterns	Medium	44.1%	Dynamic ProgrammingBacktracking
320	Generalized Abbreviation	Medium	45.2%	BacktrackingBit Manipulation
294	Flip Game II	Medium	46.5%	Backtracking
291	Word Pattern II	Hard	38.0%	Backtracking
267	Palindrome Permutation II	Medium	31.9%	Backtracking
254	Factor Combinations	Medium	43.0%	Backtracking
216	Combination Sum III	Medium	45.8%	ArrayBacktracking
212	Word Search II	Hard	23.7%	BacktrackingTrie
211	Add and Search Word - Data structure design	Medium	23.7%	BacktrackingDesignTrie
140	Word Break II	Hard	23.6%	Dynamic ProgrammingBacktracking
131	Palindrome Partitioning	Medium	34.0%	Backtracking
126	Word Ladder II	Hard	14.4%	ArrayStringBacktrackingBreadth-first Search
93	Restore IP Addresses	Medium	27.7%	StringBacktracking
90	Subsets II	Medium	36.9%	ArrayBacktracking
89	Gray Code	Medium	41.6%	Backtracking
79	Word Search	Medium	27.2%	ArrayBacktracking
78	Subsets	Medium	41.8%	ArrayBacktrackingBit Manipulation
77	Combinations	Medium	40.2%	Backtracking
60	Permutation Sequence	Medium	28.9%	MathBacktracking
52	N-Queens II	Hard	45.5%	Backtracking
51	N-Queens	Hard	31.7%	Backtracking
47	Permutations II	Medium	33.4%	Backtracking
46	Permutations	Medium	44.8%	Backtracking
44	Wildcard Matching	Hard	20.4%	StringDynamic ProgrammingBacktrackingGreedy
40	Combination Sum II	Medium	34.4%	ArrayBacktracking
39	Combination Sum	Medium	39.5%	ArrayBacktracking
37	Sudoku Solver	Hard	30.8%	Hash TableBacktracking
22	Generate Parentheses	Medium	45.9%	StringBacktracking
17	Letter Combinations of a Phone Number	Medium	35.1%	StringBacktracking
96	Unique Binary Search Trees	Medium	41.3%	Dynamic ProgrammingTree
97	Interleaving String	Hard	24.8%	StringDynamic Programming
115	Distinct Subsequences	Hard	31.7%	StringDynamic Programming
120	Triangle	Medium	34.1%	ArrayDynamic Programming
121	Best Time to Buy and Sell Stock	Easy	41.7%	ArrayDynamic Programming
123	Best Time to Buy and Sell Stock III	Hard	29.6%	ArrayDynamic Programming
132	Palindrome Partitioning II	Hard	24.4%	Dynamic Programming
139	Word Break	Medium	30.4%	Dynamic Programming
140	Word Break II	Hard	23.6%	Dynamic ProgrammingBacktracking
152	Maximum Product Subarray	Medium	26.0%	ArrayDynamic Programming
174	Dungeon Game	Hard	23.9%	Binary SearchDynamic Programming
188	Best Time to Buy and Sell Stock IV	Hard	24.4%	Dynamic Programming
198	House Robber	Easy	39.3%	Dynamic Programming
213	House Robber II	Medium	34.2%	Dynamic Programming
221	Maximal Square	Medium	29.4%	Dynamic Programming
553	Optimal Division	Medium	55.1%	MathString
537	Complex Number Multiplication	Medium	64.0%	MathString
535	Encode and Decode TinyURL	Medium	74.2%	Hash TableMath
523	Continuous Subarray Sum	Medium	23.0%	MathDynamic Programming
517	Super Washing Machines	Hard	36.5%	MathDynamic Programming
507	Perfect Number	Easy	33.8%	Math
483	Smallest Good Base	Hard	33.3%	MathBinary Search
469	Convex Polygon	Medium	32.9%	Math
462	Minimum Moves to Equal Array Elements II	Medium	51.8%	Math
453	Minimum Moves to Equal Array Elements	Easy	47.5%	Math
441	Arranging Coins	Easy	36.3%	MathBinary Search
423	Reconstruct Original Digits from English	Medium	44.5%	Math
415	Add Strings	Easy	41.5%	Math
413	Arithmetic Slices	Medium	54.6%	MathDynamic Programming
400	Nth Digit	Easy	30.0%	Math
397	Integer Replacement	Medium	30.3%	MathBit Manipulation
396	Rotate Function	Medium	33.3%	Math
372	Super Pow	Medium	34.5%	Math
368	Largest Divisible Subset	Medium	33.8%	MathDynamic Programming
367	Valid Perfect Square	Easy	38.4%	MathBinary Search
365	Water and Jug Problem	Medium	27.7%	Math
360	Sort Transformed Array	Medium	44.2%	MathTwo Pointers
357	Count Numbers with Unique Digits	Medium	46.1%	MathDynamic ProgrammingBacktracking
356	Line Reflection	Medium	30.1%	Hash TableMath
343	Integer Break	Medium	46.2%	MathDynamic Programming
335	Self Crossing	Hard	25.6%	Math
326	Power of Three	Easy	40.4%	Math
319	Bulb Switcher	Medium	42.6%	MathBrainteaser
313	Super Ugly Number	Medium	37.9%	MathHeap
296	Best Meeting Point	Hard	51.9%	MathSort
279	Perfect Squares	Medium	37.3%	MathDynamic ProgrammingBreadth-first Search
273	Integer to English Words	Hard	22.3%	MathString
268	Missing Number	Easy	44.3%	ArrayMathBit Manipulation
264	Ugly Number II	Medium	32.9%	MathDynamic ProgrammingHeap
263	Ugly Number	Easy	39.4%	Math
258	Add Digits	Easy	51.4%	Math
248	Strobogrammatic Number III	Hard	32.1%	MathRecursion
247	Strobogrammatic Number II	Medium	40.3%	MathRecursion
246	Strobogrammatic Number	Easy	40.0%	Hash TableMath
233	Number of Digit One	Hard	28.6%	Math
231	Power of Two	Easy	40.3%	MathBit Manipulation
224	Basic Calculator	Hard	27.5%	MathStack
223	Rectangle Area	Medium	33.2%	Math
204	Count Primes	Easy	26.7%	Hash TableMath
202	Happy Number	Easy	40.9%	Hash TableMath
172	Factorial Trailing Zeroes	Easy	36.3%	Math
171	Excel Sheet Column Number	Easy	47.6%	Math
168	Excel Sheet Column Title	Easy	26.5%	Math
166	Fraction to Recurring Decimal	Medium	17.7%	Hash TableMath
149	Max Points on a Line	Hard	15.3%	Hash TableMath
69	Sqrt(x)	Easy	28.0%	MathBinary Search
67	Add Binary	Easy	33.0%	MathString
66	Plus One	Easy	38.9%	ArrayMath
65	Valid Number	Hard	12.8%	MathString
60	Permutation Sequence	Medium	28.9%	MathBacktracking
50	Pow(x, n)	Medium	26.1%	MathBinary Search
43	Multiply Strings	Medium	27.5%	MathString
29	Divide Two Integers	Medium	15.9%	MathBinary Search
13	Roman to Integer	Easy	46.4%	MathString
12	Integer to Roman	Medium	45.3%	MathString
256	Paint House	Easy	46.2%	Dynamic Programming
264	Ugly Number II	Medium	32.9%	MathDynamic ProgrammingHeap
265	Paint House II	Hard	38.0%	Dynamic Programming
276	Paint Fence	Easy	34.6%	Dynamic Programming
279	Perfect Squares	Medium	37.3%	MathDynamic ProgrammingBreadth-first Search
300	Longest Increasing Subsequence	Medium	38.6%	Binary SearchDynamic Programming
303	Range Sum Query - Immutable	Easy	30.4%	Dynamic Programming
304	Range Sum Query 2D - Immutable	Medium	25.8%	Dynamic Programming
309	Best Time to Buy and Sell Stock with Cooldown	Medium	41.1%	Dynamic Programming
312	Burst Balloons	Hard	43.0%	Divide and ConquerDynamic Programming
321	Create Maximum Number	Hard	24.6%	Dynamic ProgrammingGreedy
322	Coin Change	Medium	26.7%	Dynamic Programming
338	Counting Bits	Medium	61.6%	Dynamic ProgrammingBit Manipulation
343	Integer Break	Medium	46.2%	MathDynamic Programming
351	Android Unlock Patterns	Medium	44.1%	Dynamic ProgrammingBacktracking
354	Russian Doll Envelopes	Hard	32.4%	Binary SearchDynamic Programming
357	Count Numbers with Unique Digits	Medium	46.1%	MathDynamic ProgrammingBacktracking
361	Bomb Enemy	Medium	39.1%	Dynamic Programming
363	Max Sum of Rectangle No Larger Than K	Hard	33.3%	Binary SearchDynamic ProgrammingQueue
368	Largest Divisible Subset	Medium	33.8%	MathDynamic Programming
375	Guess Number Higher or Lower II	Medium	35.8%	Dynamic ProgrammingMinimax
376	Wiggle Subsequence	Medium	35.9%	Dynamic ProgrammingGreedy
377	Combination Sum IV	Medium	42.2%	Dynamic Programming
549	Binary Tree Longest Consecutive Sequence II	Medium	41.3%	Tree
545	Boundary of Binary Tree	Medium	31.7%	Tree
543	Diameter of Binary Tree	Easy	44.4%	Tree
538	Convert BST to Greater Tree	Easy	49.4%	Tree
536	Construct Binary Tree from String	Medium	42.6%	StringTree
515	Find Largest Value in Each Tree Row	Medium	55.0%	TreeDepth-first SearchBreadth-first Search
513	Find Bottom Left Tree Value	Medium	56.1%	TreeDepth-first SearchBreadth-first Search
508	Most Frequent Subtree Sum	Medium	52.3%	Hash TableTree
501	Find Mode in Binary Search Tree	Easy	37.7%	Tree
450	Delete Node in a BST	Medium	37.1%	Tree
449	Serialize and Deserialize BST	Medium	42.5%	Tree
437	Path Sum III	Easy	39.9%	Tree
404	Sum of Left Leaves	Easy	47.2%	Tree
366	Find Leaves of Binary Tree	Medium	60.1%	TreeDepth-first Search
337	House Robber III	Medium	43.9%	TreeDepth-first Search
333	Largest BST Subtree	Medium	30.5%	Tree
298	Binary Tree Longest Consecutive Sequence	Medium	41.2%	Tree
297	Serialize and Deserialize Binary Tree	Hard	33.8%	TreeDesign
285	Inorder Successor in BST	Medium	36.2%	Tree
272	Closest Binary Search Tree Value II	Hard	39.3%	StackTree
270	Closest Binary Search Tree Value	Easy	39.9%	Binary SearchTree
257	Binary Tree Paths	Easy	39.3%	TreeDepth-first Search
255	Verify Preorder Sequence in Binary Search Tree	Medium	40.5%	StackTree
250	Count Univalue Subtrees	Medium	42.5%	Tree
236	Lowest Common Ancestor of a Binary Tree	Medium	30.0%	Tree
235	Lowest Common Ancestor of a Binary Search Tree	Easy	39.3%	Tree
230	Kth Smallest Element in a BST	Medium	44.2%	Binary SearchTree
226	Invert Binary Tree	Easy	52.3%	Tree
222	Count Complete Tree Nodes	Medium	27.6%	Binary SearchTree
199	Binary Tree Right Side View	Medium	41.5%	TreeDepth-first SearchBreadth-first Search
173	Binary Search Tree Iterator	Medium	42.0%	StackTreeDesign
156	Binary Tree Upside Down	Medium	44.9%	Tree
145	Binary Tree Postorder Traversal	Hard	40.6%	StackTree
144	Binary Tree Preorder Traversal	Medium	45.5%	StackTree
129	Sum Root to Leaf Numbers	Medium	37.0%	TreeDepth-first Search
124	Binary Tree Maximum Path Sum	Hard	26.4%	TreeDepth-first Search
117	Populating Next Right Pointers in Each Node II	Medium	33.8%	TreeDepth-first Search
392	Is Subsequence	Medium	44.6%	Binary SearchDynamic ProgrammingGreedy
114	Flatten Binary Tree to Linked List	Medium	35.5%	TreeDepth-first Search
113	Path Sum II	Medium	34.3%	TreeDepth-first Search
112	Path Sum	Easy	34.2%	TreeDepth-first Search
111	Minimum Depth of Binary Tree	Easy	33.3%	TreeDepth-first SearchBreadth-first Search
110	Balanced Binary Tree	Easy	37.8%	TreeDepth-first Search
108	Convert Sorted Array to Binary Search Tree	Easy	42.5%	TreeDepth-first Search
535	Encode and Decode TinyURL	Medium	74.2%	Hash TableMath
106	Construct Binary Tree from Inorder and Postorder Traversal	Medium	32.4%	ArrayTreeDepth-first Search
105	Construct Binary Tree from Preorder and Inorder Traversal	Medium	32.6%	ArrayTreeDepth-first Search
104	Maximum Depth of Binary Tree	Easy	53.1%	TreeDepth-first Search
103	Binary Tree Zigzag Level Order Traversal	Medium	35.2%	StackTreeBreadth-first Search
102	Binary Tree Level Order Traversal	Medium	40.6%	TreeBreadth-first Search
101	Symmetric Tree	Easy	39.2%	TreeDepth-first SearchBreadth-first Search
100	Same Tree	Easy	46.8%	TreeDepth-first Search
99	Recover Binary Search Tree	Hard	30.2%	TreeDepth-first Search
98	Validate Binary Search Tree	Medium	23.6%	TreeDepth-first Search
96	Unique Binary Search Trees	Medium	41.3%	Dynamic ProgrammingTree
95	Unique Binary Search Trees II	Medium	31.7%	Dynamic ProgrammingTree
94	Binary Tree Inorder Traversal	Medium	47.4%	Hash TableStackTree
403	Frog Jump	Hard	32.4%	Dynamic Programming
410	Split Array Largest Sum	Hard	38.2%	Binary SearchDynamic Programming
532	K-diff Pairs in an Array	Easy	28.2%	ArrayTwo Pointers
524	Longest Word in Dictionary through Deleting	Medium	42.9%	Two PointersSort
487	Max Consecutive Ones II	Medium	45.5%	Two Pointers
360	Sort Transformed Array	Medium	44.2%	MathTwo Pointers
350	Intersection of Two Arrays II	Easy	44.7%	Hash TableTwo PointersBinary SearchSort
349	Intersection of Two Arrays	Easy	47.5%	Hash TableTwo PointersBinary SearchSort
345	Reverse Vowels of a String	Easy	38.6%	Two PointersString
344	Reverse String	Easy	59.5%	Two PointersString
287	Find the Duplicate Number	Medium	43.7%	ArrayTwo PointersBinary Search
283	Move Zeroes	Easy	50.4%	ArrayTwo Pointers
259	3Sum Smaller	Medium	41.6%	ArrayTwo Pointers
234	Palindrome Linked List	Easy	33.0%	Linked ListTwo Pointers
209	Minimum Size Subarray Sum	Medium	31.2%	ArrayTwo PointersBinary Search
167	Two Sum II - Input array is sorted	Easy	47.1%	ArrayTwo PointersBinary Search
159	Longest Substring with At Most Two Distinct Characters	Hard	41.6%	Hash TableTwo PointersString
142	Linked List Cycle II	Medium	30.9%	Linked ListTwo Pointers
141	Linked List Cycle	Easy	35.3%	Linked ListTwo Pointers
125	Valid Palindrome	Easy	26.5%	Two PointersString
88	Merge Sorted Array	Easy	32.1%	ArrayTwo Pointers
86	Partition List	Medium	33.0%	Linked ListTwo Pointers
80	Remove Duplicates from Sorted Array II	Medium	36.3%	ArrayTwo Pointers
76	Minimum Window Substring	Hard	25.9%	Hash TableTwo PointersString
75	Sort Colors	Medium	38.3%	ArrayTwo PointersSort
61	Rotate List	Medium	24.3%	Linked ListTwo Pointers
42	Trapping Rain Water	Hard	37.0%	ArrayTwo PointersStack
30	Substring with Concatenation of All Words	Hard	22.0%	Hash TableTwo PointersString
28	Implement strStr()	Easy	28.4%	Two PointersString
27	Remove Element	Easy	39.6%	ArrayTwo Pointers
26	Remove Duplicates from Sorted Array	Easy	35.4%	ArrayTwo Pointers
19	Remove Nth Node From End of List	Medium	33.8%	Linked ListTwo Pointers
18	4Sum	Medium	27.0%	ArrayHash TableTwo Pointers
16	3Sum Closest	Medium	31.3%	ArrayTwo Pointers
15	3Sum	Medium	21.8%	ArrayTwo Pointers
11	Container With Most Water	Medium	36.8%	ArrayTwo Pointers
413	Arithmetic Slices	Medium	54.6%	MathDynamic Programming
416	Partition Equal Subset Sum	Medium	39.3%	Dynamic Programming
418	Sentence Screen Fitting	Medium	27.8%	Dynamic Programming
446	Arithmetic Slices II - Subsequence	Hard	27.2%	Dynamic Programming
464	Can I Win	Medium	25.0%	Dynamic ProgrammingMinimax
466	Count The Repetitions	Hard	28.0%	Dynamic Programming
467	Unique Substrings in Wraparound String	Medium	32.9%	Dynamic Programming
471	Encode String with Shortest Length	Hard	42.5%	Dynamic Programming
472	Concatenated Words	Hard	30.3%	Dynamic ProgrammingDepth-first SearchTrie
474	Ones and Zeroes	Medium	38.9%	Dynamic Programming
547	Friend Circles	Medium	49.2%	Depth-first SearchUnion Find
546	Remove Boxes	Hard	34.0%	Dynamic ProgrammingDepth-first Search
542	01 Matrix	Medium	33.3%	Depth-first SearchBreadth-first Search
533	Lonely Pixel II	Medium	44.2%	ArrayDepth-first Search
531	Lonely Pixel I	Medium	55.3%	ArrayDepth-first Search
529	Minesweeper	Medium	49.5%	Depth-first SearchBreadth-first Search
515	Find Largest Value in Each Tree Row	Medium	55.0%	TreeDepth-first SearchBreadth-first Search
514	Freedom Trail	Hard	39.2%	Divide and ConquerDynamic ProgrammingDepth-first Search
513	Find Bottom Left Tree Value	Medium	56.1%	TreeDepth-first SearchBreadth-first Search
505	The Maze II	Medium	37.7%	Depth-first SearchBreadth-first Search
499	The Maze III	Hard	32.7%	Depth-first SearchBreadth-first Search
494	Target Sum	Medium	43.4%	Dynamic ProgrammingDepth-first Search
491	Increasing Subsequences	Medium	38.8%	Depth-first Search
490	The Maze	Medium	43.2%	Depth-first SearchBreadth-first Search
488	Zuma Game	Hard	37.5%	Depth-first Search
473	Matchsticks to Square	Medium	35.5%	Depth-first Search
472	Concatenated Words	Hard	30.3%	Dynamic ProgrammingDepth-first SearchTrie
439	Ternary Expression Parser	Medium	51.1%	StackDepth-first Search
417	Pacific Atlantic Water Flow	Medium	33.8%	Depth-first SearchBreadth-first Search
394	Decode String	Medium	41.5%	StackDepth-first Search
366	Find Leaves of Binary Tree	Medium	60.1%	TreeDepth-first Search
364	Nested List Weight Sum II	Medium	52.9%	Depth-first Search
339	Nested List Weight Sum	Easy	62.4%	Depth-first Search
337	House Robber III	Medium	43.9%	TreeDepth-first Search
332	Reconstruct Itinerary	Medium	29.4%	Depth-first SearchGraph
329	Longest Increasing Path in a Matrix	Hard	36.7%	Depth-first SearchTopological SortMemoization
323	Number of Connected Components in an Undirected Graph	Medium	48.2%	Depth-first SearchBreadth-first SearchUnion FindGraph
301	Remove Invalid Parentheses	Hard	35.3%	Depth-first SearchBreadth-first Search
261	Graph Valid Tree	Medium	38.0%	Depth-first SearchBreadth-first SearchUnion FindGraph
257	Binary Tree Paths	Easy	39.3%	TreeDepth-first Search
210	Course Schedule II	Medium	28.7%	Depth-first SearchBreadth-first SearchGraphTopological Sort
207	Course Schedule	Medium	32.6%	Depth-first SearchBreadth-first SearchGraphTopological Sort
200	Number of Islands	Medium	35.2%	Depth-first SearchBreadth-first SearchUnion Find
199	Binary Tree Right Side View	Medium	41.5%	TreeDepth-first SearchBreadth-first Search
133	Clone Graph	Medium	25.1%	Depth-first SearchBreadth-first SearchGraph
129	Sum Root to Leaf Numbers	Medium	37.0%	TreeDepth-first Search
124	Binary Tree Maximum Path Sum	Hard	26.4%	TreeDepth-first Search
117	Populating Next Right Pointers in Each Node II	Medium	33.8%	TreeDepth-first Search
116	Populating Next Right Pointers in Each Node	Medium	36.9%	TreeDepth-first Search
114	Flatten Binary Tree to Linked List	Medium	35.5%	TreeDepth-first Search
113	Path Sum II	Medium	34.3%	TreeDepth-first Search
112	Path Sum	Easy	34.2%	TreeDepth-first Search
111	Minimum Depth of Binary Tree	Easy	33.3%	TreeDepth-first SearchBreadth-first Search
110	Balanced Binary Tree	Easy	37.8%	TreeDepth-first Search
109	Convert Sorted List to Binary Search Tree	Medium	34.4%	Linked ListDepth-first Search
108	Convert Sorted Array to Binary Search Tree	Easy	42.5%	TreeDepth-first Search
106	Construct Binary Tree from Inorder and Postorder Traversal	Medium	32.4%	ArrayTreeDepth-first Search
105	Construct Binary Tree from Preorder and Inorder Traversal	Medium	32.6%	ArrayTreeDepth-first Search
104	Maximum Depth of Binary Tree	Easy	53.1%	TreeDepth-first Search
101	Symmetric Tree	Easy	39.2%	TreeDepth-first SearchBreadth-first Search
100	Same Tree	Easy	46.8%	TreeDepth-first Search
99	Recover Binary Search Tree	Hard	30.2%	TreeDepth-first Search
98	Validate Binary Search Tree	Medium	23.6%	TreeDepth-first Search
486	Predict the Winner	Medium	45.1%	Dynamic ProgrammingMinimax
494	Target Sum	Medium	43.4%	Dynamic ProgrammingDepth-first Search
514	Freedom Trail	Hard	39.2%	Divide and ConquerDynamic ProgrammingDepth-first Search
516	Longest Palindromic Subsequence	Medium	42.7%	Dynamic Programming
517	Super Washing Machines	Hard	36.5%	MathDynamic Programming
523	Continuous Subarray Sum	Medium	23.0%	MathDynamic Programming
546	Remove Boxes	Hard	34.0%	Dynamic ProgrammingDepth-first Search
552	Student Attendance Record II	Hard	31.4%	Dynamic Programming
11	Container With Most Water	Medium	36.8%	ArrayTwo Pointers
15	3Sum	Medium	21.8%	ArrayTwo Pointers
16	3Sum Closest	Medium	31.3%	ArrayTwo Pointers
18	4Sum	Medium	27.0%	ArrayHash TableTwo Pointers
26	Remove Duplicates from Sorted Array	Easy	35.4%	ArrayTwo Pointers
27	Remove Element	Easy	39.6%	ArrayTwo Pointers
31	Next Permutation	Medium	28.8%	Array
33	Search in Rotated Sorted Array	Medium	32.1%	ArrayBinary Search
34	Search for a Range	Medium	31.4%	ArrayBinary Search
35	Search Insert Position	Easy	39.8%	ArrayBinary Search
39	Combination Sum	Medium	39.5%	ArrayBacktracking
40	Combination Sum II	Medium	34.4%	ArrayBacktracking
41	First Missing Positive	Hard	25.6%	Array
548	Split Array with Equal Sum	Medium	36.8%	Array
533	Lonely Pixel II	Medium	44.2%	ArrayDepth-first Search
532	K-diff Pairs in an Array	Easy	28.2%	ArrayTwo Pointers
531	Lonely Pixel I	Medium	55.3%	ArrayDepth-first Search
495	Teemo Attacking	Medium	51.5%	Array
485	Max Consecutive Ones	Easy	53.9%	Array
448	Find All Numbers Disappeared in an Array	Easy	51.2%	Array
442	Find All Duplicates in an Array	Medium	56.1%	Array
414	Third Maximum Number	Easy	27.9%	Array
381	Insert Delete GetRandom O(1) - Duplicates allowed	Hard	29.0%	ArrayHash TableDesign
380	Insert Delete GetRandom O(1)	Medium	39.3%	ArrayHash TableDesign
370	Range Addition	Medium	56.2%	Array
289	Game of Life	Medium	37.1%	Array
287	Find the Duplicate Number	Medium	43.7%	ArrayTwo PointersBinary Search
283	Move Zeroes	Easy	50.4%	ArrayTwo Pointers
280	Wiggle Sort	Medium	57.6%	ArraySort
277	Find the Celebrity	Medium	35.6%	Array
268	Missing Number	Easy	44.3%	ArrayMathBit Manipulation
259	3Sum Smaller	Medium	41.6%	ArrayTwo Pointers
245	Shortest Word Distance III	Medium	50.6%	Array
243	Shortest Word Distance	Easy	52.8%	Array
238	Product of Array Except Self	Medium	49.6%	Array
229	Majority Element II	Medium	28.7%	Array
228	Summary Ranges	Medium	30.5%	Array
219	Contains Duplicate II	Easy	32.6%	ArrayHash Table
217	Contains Duplicate	Easy	46.1%	ArrayHash Table
216	Combination Sum III	Medium	45.8%	ArrayBacktracking
209	Minimum Size Subarray Sum	Medium	31.2%	ArrayTwo PointersBinary Search
189	Rotate Array	Easy	24.9%	Array
169	Majority Element	Easy	47.0%	ArrayDivide and ConquerBit Manipulation
167	Two Sum II - Input array is sorted	Easy	47.1%	ArrayTwo PointersBinary Search
163	Missing Ranges	Medium	23.9%	Array
162	Find Peak Element	Medium	37.9%	ArrayBinary Search
154	Find Minimum in Rotated Sorted Array II	Hard	37.4%	ArrayBinary Search
153	Find Minimum in Rotated Sorted Array	Medium	40.2%	ArrayBinary Search
152	Maximum Product Subarray	Medium	26.0%	ArrayDynamic Programming
128	Longest Consecutive Sequence	Hard	37.3%	ArrayUnion Find
126	Word Ladder II	Hard	14.4%	ArrayStringBacktrackingBreadth-first Search
123	Best Time to Buy and Sell Stock III	Hard	29.6%	ArrayDynamic Programming
122	Best Time to Buy and Sell Stock II	Easy	47.4%	ArrayGreedy
121	Best Time to Buy and Sell Stock	Easy	41.7%	ArrayDynamic Programming
120	Triangle	Medium	34.1%	ArrayDynamic Programming
119	Pascal's Triangle II	Easy	37.3%	Array
118	Pascal's Triangle	Easy	39.0%	Array
106	Construct Binary Tree from Inorder and Postorder Traversal	Medium	32.4%	ArrayTreeDepth-first Search
105	Construct Binary Tree from Preorder and Inorder Traversal	Medium	32.6%	ArrayTreeDepth-first Search
90	Subsets II	Medium	36.9%	ArrayBacktracking
88	Merge Sorted Array	Easy	32.1%	ArrayTwo Pointers
85	Maximal Rectangle	Hard	28.5%	ArrayHash TableDynamic ProgrammingStack
84	Largest Rectangle in Histogram	Hard	27.0%	ArrayStack
81	Search in Rotated Sorted Array II	Medium	32.7%	ArrayBinary Search
80	Remove Duplicates from Sorted Array II	Medium	36.3%	ArrayTwo Pointers
79	Word Search	Medium	27.2%	ArrayBacktracking
78	Subsets	Medium	41.8%	ArrayBacktrackingBit Manipulation
75	Sort Colors	Medium	38.3%	ArrayTwo PointersSort
74	Search a 2D Matrix	Medium	34.9%	ArrayBinary Search
73	Set Matrix Zeroes	Medium	36.1%	Array
66	Plus One	Easy	38.9%	ArrayMath
64	Minimum Path Sum	Medium	38.9%	ArrayDynamic Programming
63	Unique Paths II	Medium	31.9%	ArrayDynamic Programming
62	Unique Paths	Medium	41.7%	ArrayDynamic Programming
59	Spiral Matrix II	Medium	40.1%	Array
57	Insert Interval	Hard	28.1%	ArraySort
56	Merge Intervals	Medium	30.7%	ArraySort
55	Jump Game	Medium	29.5%	ArrayGreedy
54	Spiral Matrix	Medium	26.4%	Array
53	Maximum Subarray	Easy	39.8%	ArrayDivide and ConquerDynamic Programming
48	Rotate Image	Medium	39.5%	Array
45	Jump Game II	Hard	26.2%	ArrayGreedy
42	Trapping Rain Water	Hard	37.0%	ArrayTwo PointersStack
694	Number of Distinct Islands	Medium	43.5%	Hash TableDepth-first Search
560	Subarray Sum Equals K	Medium	40.2%	ArrayMap
563	Binary Tree Tilt	Easy	47.1%	Tree
562	Longest Line of Consecutive One in Matrix	Medium	40.6%	Array
561	Array Partition I	Easy	66.8%	Array
572	Subtree of Another Tree	Easy	40.8%	Tree
605	Can Place Flowers	Easy	30.0%	Array
575	Distribute Candies	Easy	58.7%	Hash Table
594	Longest Harmonious Subsequence	Easy	41.1%	Hash Table
604	Design Compressed String Iterator	Easy	32.4%	Design
588	Design In-Memory File System	Hard	34.7%	Design
599	Minimum Index Sum of Two Lists	Easy	46.3%	Hash Table
598	Range Addition II	Easy	48.2%	Math
593	Valid Square	Medium	40.0%	Math
592	Fraction Addition and Subtraction	Medium	46.4%	Math
573	Squirrel Simulation	Medium	52.3%	Math
582	Kill Process	Medium	49.5%	TreeQueue
566	Reshape the Matrix	Easy	58.5%	Array
581	Shortest Unsorted Continuous Subarray	Easy	29.5%	Array
567	Permutation in String	Medium	36.6%	Two Pointers
576	Out of Boundary Paths	Medium	30.9%	Dynamic ProgrammingDepth-first Search
568	Maximum Vacation Days	Hard	39.9%	Dynamic Programming
576	Out of Boundary Paths	Medium	30.9%	Dynamic ProgrammingDepth-first Search
600	Non-negative Integers without Consecutive Ones	Hard	30.4%	Dynamic Programming
662	Maximum Width of Binary Tree	Medium	37.7%	Tree
647	Palindromic Substrings	Medium	55.8%	StringDynamic Programming
639	Decode Ways II	Hard	23.6%	Dynamic Programming
638	Shopping Offers	Medium	42.9%	Dynamic ProgrammingDepth-first Search
629	K Inverse Pairs Array	Hard	26.7%	Dynamic Programming
621	Task Scheduler	Medium	42.1%	ArrayGreedyQueue
624	Maximum Distance in Arrays	Easy	34.1%	ArrayHash Table
642	Design Search Autocomplete System	Hard	30.0%	DesignTrie
635	Design Log Storage System	Medium	48.4%	StringDesign
631	Design Excel Sum Formula	Hard	26.6%	Design
628	Maximum Product of Three Numbers	Easy	45.0%	ArrayMath
643	Maximum Average Subarray I	Easy	37.7%	Array
644	Maximum Average Subarray II	Hard	22.1%	ArrayBinary Search
644	Maximum Average Subarray II	Hard	22.1%	ArrayBinary Search
609	Find Duplicate File in System	Medium	52.5%	Hash TableString
645	Set Mismatch	Easy	40.3%	Hash TableMath
640	Solve the Equation	Medium	39.0%	Math
638	Shopping Offers	Medium	42.9%	Dynamic ProgrammingDepth-first Search
634	Find the Derangement of An Array	Medium	33.8%	Math
633	Sum of Square Numbers	Easy	32.2%	Math
628	Maximum Product of Three Numbers	Easy	45.0%	ArrayMath
625	Minimum Factorization	Medium	30.7%	MathRecursion
624	Maximum Distance in Arrays	Easy	34.1%	ArrayHash Table
632	Smallest Range	Hard	42.4%	Hash TableTwo PointersString
645	Set Mismatch	Easy	40.3%	Hash TableMath
646	Maximum Length of Pair Chain	Medium	47.7%	Dynamic Programming
637	Average of Levels in Binary Tree	Easy	55.8%	Tree
632	Smallest Range	Hard	42.4%	Hash TableTwo PointersString
623	Add One Row to Tree	Medium	46.6%	Tree
617	Merge Two Binary Trees	Easy	67.9%	Tree
611	Valid Triangle Number	Medium	41.7%	Array
606	Construct String from Binary Tree	Easy	49.8%	StringTree
690	Employee Importance	Easy	55.5%	Hash TableDepth-first SearchBreadth-first Search
691	Stickers to Spell Word	Hard	31.7%	Dynamic ProgrammingBacktracking
688	Knight Probability in Chessboard	Medium	38.3%	Dynamic Programming
673	Number of Longest Increasing Subsequence	Medium	30.9%	Dynamic Programming
652	Find Duplicate Subtrees	Medium	34.9%	Tree
653	Two Sum IV - Input is a BST	Easy	50.7%	Tree
654	Maximum Binary Tree	Medium	70.2%	Tree
655	Print Binary Tree	Medium	50.6%	Tree
676	Implement Magic Dictionary	Medium	50.0%	Hash TableTrie
663	Equal Tree Partition	Medium	36.6%	Tree
666	Path Sum IV	Medium	49.4%	Tree
669	Trim a Binary Search Tree	Easy	58.4%	Tree
671	Second Minimum Node In a Binary Tree	Easy	41.9%	Tree
684	Redundant Connection	Medium	35.8%	TreeUnion FindGraph
685	Redundant Connection II	Hard	28.8%	TreeDepth-first SearchUnion FindGraph
687	Longest Univalue Path	Easy	32.3%	TreeRecursion
648	Replace Words	Medium	47.7%	Hash TableTrie
650	2 Keys Keyboard	Medium	44.1%	Dynamic Programming
651	4 Keys Keyboard	Medium	47.9%	MathDynamic ProgrammingGreedy
656	Coin Path	Hard	24.5%	Dynamic Programming
665	Non-decreasing Array	Easy	21.3%	Array
667	Beautiful Arrangement II	Medium	51.6%	Array
690	Employee Importance	Easy	55.5%	Hash TableDepth-first SearchBreadth-first Search
661	Image Smoother	Easy	45.8%	Array
689	Maximum Sum of 3 Non-Overlapping Subarrays	Hard	42.9%	ArrayDynamic Programming
685	Redundant Connection II	Hard	28.8%	TreeDepth-first SearchUnion FindGraph
679	24 Game	Hard	38.5%	Depth-first Search
664	Strange Printer	Hard	31.4%	Dynamic ProgrammingDepth-first Search
664	Strange Printer	Hard	31.4%	Dynamic ProgrammingDepth-first Search
670	Maximum Swap	Medium	38.4%	ArrayMath
651	4 Keys Keyboard	Medium	47.9%	MathDynamic ProgrammingGreedy
660	Remove 9	Hard	47.1%	Math
670	Maximum Swap	Medium	38.4%	ArrayMath
672	Bulb Switcher II	Medium	48.1%	Math
674	Longest Continuous Increasing Subsequence	Easy	43.0%	Array
691	Stickers to Spell Word	Hard	31.7%	Dynamic ProgrammingBacktracking
689	Maximum Sum of 3 Non-Overlapping Subarrays	Hard	42.9%	ArrayDynamic Programming
683	K Empty Slots	Hard	37.2%	ArrayBinary Search Tree
658	Find K Closest Elements	Medium	35.7%	Binary Search
668	Kth Smallest Number in Multiplication Table	Hard	37.0%	Binary Search
692	Top K Frequent Words	Medium	41.1%	Hash TableHeapTrie
694	Number of Distinct Islands	Medium	43.5%	Hash TableDepth-first Search
695	Max Area of Island	Easy	53.3%	ArrayDepth-first Search
695	Max Area of Island	Easy	53.3%	ArrayDepth-first Search
697	Degree of an Array	Easy	48.9%	Array
698	Partition to K Equal Sum Subsets	Medium	34.7%	Dynamic ProgrammingRecursion
711	Number of Distinct Islands II	Hard	26.0%	Hash TableDepth-first Search
711	Number of Distinct Islands II	Hard	26.0%	Hash TableDepth-first Search

Tag:design

ID	Title	Difficulty	Acceptance	Tags
392	Is Subsequence	Medium	44.6%	Binary SearchDynamic ProgrammingGreedy
116	Populating Next Right Pointers in Each Node	Medium	36.9%	TreeDepth-first Search
1	Two Sum	Easy	35.6%	ArrayHash Table
4	Median of Two Sorted Arrays	Hard	22.1%	ArrayBinary SearchDivide and Conquer
3	Longest Substring Without Repeating Characters	Medium	24.4%	Hash TableTwo PointersString
2	Add Two Numbers	Medium	28.0%	Linked ListMath
7	Reverse Integer	Easy	24.5%	Math
8	String to Integer (atoi)	Medium	14.0%	MathString
9	Palindrome Number	Easy	35.5%	Math
10	Regular Expression Matching	Hard	24.2%	StringDynamic ProgrammingBacktracking
4	Median of Two Sorted Arrays	Hard	22.1%	ArrayBinary SearchDivide and Conquer
1	Two Sum	Easy	35.6%	ArrayHash Table
3	Longest Substring Without Repeating Characters	Medium	24.4%	Hash TableTwo PointersString
107	Binary Tree Level Order Traversal II	Easy	40.8%	TreeBreadth-first Search
42	Trapping Rain Water	Hard	37.0%	ArrayTwo PointersStack
45	Jump Game II	Hard	26.2%	ArrayGreedy
48	Rotate Image	Medium	39.5%	Array
53	Maximum Subarray	Easy	39.8%	ArrayDivide and ConquerDynamic Programming
54	Spiral Matrix	Medium	26.4%	Array
55	Jump Game	Medium	29.5%	ArrayGreedy
56	Merge Intervals	Medium	30.7%	ArraySort
57	Insert Interval	Hard	28.1%	ArraySort
59	Spiral Matrix II	Medium	40.1%	Array
62	Unique Paths	Medium	41.7%	ArrayDynamic Programming
63	Unique Paths II	Medium	31.9%	ArrayDynamic Programming
64	Minimum Path Sum	Medium	38.9%	ArrayDynamic Programming
66	Plus One	Easy	38.9%	ArrayMath
73	Set Matrix Zeroes	Medium	36.1%	Array
74	Search a 2D Matrix	Medium	34.9%	ArrayBinary Search
75	Sort Colors	Medium	38.3%	ArrayTwo PointersSort
78	Subsets	Medium	41.8%	ArrayBacktrackingBit Manipulation
79	Word Search	Medium	27.2%	ArrayBacktracking
80	Remove Duplicates from Sorted Array II	Medium	36.3%	ArrayTwo Pointers
81	Search in Rotated Sorted Array II	Medium	32.7%	ArrayBinary Search
84	Largest Rectangle in Histogram	Hard	27.0%	ArrayStack
85	Maximal Rectangle	Hard	28.5%	ArrayHash TableDynamic ProgrammingStack
88	Merge Sorted Array	Easy	32.1%	ArrayTwo Pointers
90	Subsets II	Medium	36.9%	ArrayBacktracking
105	Construct Binary Tree from Preorder and Inorder Traversal	Medium	32.6%	ArrayTreeDepth-first Search
106	Construct Binary Tree from Inorder and Postorder Traversal	Medium	32.4%	ArrayTreeDepth-first Search
41	First Missing Positive	Hard	25.6%	Array
40	Combination Sum II	Medium	34.4%	ArrayBacktracking
39	Combination Sum	Medium	39.5%	ArrayBacktracking
35	Search Insert Position	Easy	39.8%	ArrayBinary Search
34	Search for a Range	Medium	31.4%	ArrayBinary Search
33	Search in Rotated Sorted Array	Medium	32.1%	ArrayBinary Search
31	Next Permutation	Medium	28.8%	Array
27	Remove Element	Easy	39.6%	ArrayTwo Pointers
26	Remove Duplicates from Sorted Array	Easy	35.4%	ArrayTwo Pointers
18	4Sum	Medium	27.0%	ArrayHash TableTwo Pointers
16	3Sum Closest	Medium	31.3%	ArrayTwo Pointers
15	3Sum	Medium	21.8%	ArrayTwo Pointers
11	Container With Most Water	Medium	36.8%	ArrayTwo Pointers
98	Validate Binary Search Tree	Medium	23.6%	TreeDepth-first Search
99	Recover Binary Search Tree	Hard	30.2%	TreeDepth-first Search
100	Same Tree	Easy	46.8%	TreeDepth-first Search
101	Symmetric Tree	Easy	39.2%	TreeDepth-first SearchBreadth-first Search
104	Maximum Depth of Binary Tree	Easy	53.1%	TreeDepth-first Search
105	Construct Binary Tree from Preorder and Inorder Traversal	Medium	32.6%	ArrayTreeDepth-first Search
106	Construct Binary Tree from Inorder and Postorder Traversal	Medium	32.4%	ArrayTreeDepth-first Search
94	Binary Tree Inorder Traversal	Medium	47.4%	Hash TableStackTree
85	Maximal Rectangle	Hard	28.5%	ArrayHash TableDynamic ProgrammingStack
76	Minimum Window Substring	Hard	25.9%	Hash TableTwo PointersString
49	Group Anagrams	Medium	35.9%	Hash TableString
37	Sudoku Solver	Hard	30.8%	Hash TableBacktracking
36	Valid Sudoku	Medium	36.3%	Hash Table
30	Substring with Concatenation of All Words	Hard	22.0%	Hash TableTwo PointersString
18	4Sum	Medium	27.0%	ArrayHash TableTwo Pointers
32	Longest Valid Parentheses	Hard	23.1%	StringDynamic Programming
44	Wildcard Matching	Hard	20.4%	StringDynamic ProgrammingBacktrackingGreedy
53	Maximum Subarray	Easy	39.8%	ArrayDivide and ConquerDynamic Programming
62	Unique Paths	Medium	41.7%	ArrayDynamic Programming
63	Unique Paths II	Medium	31.9%	ArrayDynamic Programming
64	Minimum Path Sum	Medium	38.9%	ArrayDynamic Programming
70	Climbing Stairs	Easy	40.3%	Dynamic Programming
108	Convert Sorted Array to Binary Search Tree	Easy	42.5%	TreeDepth-first Search
109	Convert Sorted List to Binary Search Tree	Medium	34.4%	Linked ListDepth-first Search
110	Balanced Binary Tree	Easy	37.8%	TreeDepth-first Search
111	Minimum Depth of Binary Tree	Easy	33.3%	TreeDepth-first SearchBreadth-first Search
112	Path Sum	Easy	34.2%	TreeDepth-first Search
113	Path Sum II	Medium	34.3%	TreeDepth-first Search
114	Flatten Binary Tree to Linked List	Medium	35.5%	TreeDepth-first Search
116	Populating Next Right Pointers in Each Node	Medium	36.9%	TreeDepth-first Search
11	Container With Most Water	Medium	36.8%	ArrayTwo Pointers
15	3Sum	Medium	21.8%	ArrayTwo Pointers
16	3Sum Closest	Medium	31.3%	ArrayTwo Pointers
18	4Sum	Medium	27.0%	ArrayHash TableTwo Pointers
19	Remove Nth Node From End of List	Medium	33.8%	Linked ListTwo Pointers
26	Remove Duplicates from Sorted Array	Easy	35.4%	ArrayTwo Pointers
27	Remove Element	Easy	39.6%	ArrayTwo Pointers
28	Implement strStr()	Easy	28.4%	Two PointersString
30	Substring with Concatenation of All Words	Hard	22.0%	Hash TableTwo PointersString
42	Trapping Rain Water	Hard	37.0%	ArrayTwo PointersStack
61	Rotate List	Medium	24.3%	Linked ListTwo Pointers
75	Sort Colors	Medium	38.3%	ArrayTwo PointersSort
76	Minimum Window Substring	Hard	25.9%	Hash TableTwo PointersString
80	Remove Duplicates from Sorted Array II	Medium	36.3%	ArrayTwo Pointers
86	Partition List	Medium	33.0%	Linked ListTwo Pointers
88	Merge Sorted Array	Easy	32.1%	ArrayTwo Pointers
94	Binary Tree Inorder Traversal	Medium	47.4%	Hash TableStackTree
95	Unique Binary Search Trees II	Medium	31.7%	Dynamic ProgrammingTree
96	Unique Binary Search Trees	Medium	41.3%	Dynamic ProgrammingTree
72	Edit Distance	Hard	32.0%	StringDynamic Programming
85	Maximal Rectangle	Hard	28.5%	ArrayHash TableDynamic ProgrammingStack
87	Scramble String	Hard	29.4%	StringDynamic Programming
98	Validate Binary Search Tree	Medium	23.6%	TreeDepth-first Search
99	Recover Binary Search Tree	Hard	30.2%	TreeDepth-first Search
100	Same Tree	Easy	46.8%	TreeDepth-first Search
101	Symmetric Tree	Easy	39.2%	TreeDepth-first SearchBreadth-first Search
102	Binary Tree Level Order Traversal	Medium	40.6%	TreeBreadth-first Search
103	Binary Tree Zigzag Level Order Traversal	Medium	35.2%	StackTreeBreadth-first Search
104	Maximum Depth of Binary Tree	Easy	53.1%	TreeDepth-first Search
105	Construct Binary Tree from Preorder and Inorder Traversal	Medium	32.6%	ArrayTreeDepth-first Search
106	Construct Binary Tree from Inorder and Postorder Traversal	Medium	32.4%	ArrayTreeDepth-first Search
108	Convert Sorted Array to Binary Search Tree	Easy	42.5%	TreeDepth-first Search
110	Balanced Binary Tree	Easy	37.8%	TreeDepth-first Search
111	Minimum Depth of Binary Tree	Easy	33.3%	TreeDepth-first SearchBreadth-first Search
112	Path Sum	Easy	34.2%	TreeDepth-first Search
113	Path Sum II	Medium	34.3%	TreeDepth-first Search
114	Flatten Binary Tree to Linked List	Medium	35.5%	TreeDepth-first Search
10	Regular Expression Matching	Hard	24.2%	StringDynamic ProgrammingBacktracking
12	Integer to Roman	Medium	45.3%	MathString
13	Roman to Integer	Easy	46.4%	MathString
29	Divide Two Integers	Medium	15.9%	MathBinary Search
43	Multiply Strings	Medium	27.5%	MathString
50	Pow(x, n)	Medium	26.1%	MathBinary Search
60	Permutation Sequence	Medium	28.9%	MathBacktracking
65	Valid Number	Hard	12.8%	MathString
66	Plus One	Easy	38.9%	ArrayMath
67	Add Binary	Easy	33.0%	MathString
69	Sqrt(x)	Easy	28.0%	MathBinary Search
115	Distinct Subsequences	Hard	31.7%	StringDynamic Programming
97	Interleaving String	Hard	24.8%	StringDynamic Programming
96	Unique Binary Search Trees	Medium	41.3%	Dynamic ProgrammingTree
81	Search in Rotated Sorted Array II	Medium	32.7%	ArrayBinary Search
74	Search a 2D Matrix	Medium	34.9%	ArrayBinary Search
69	Sqrt(x)	Easy	28.0%	MathBinary Search
50	Pow(x, n)	Medium	26.1%	MathBinary Search
35	Search Insert Position	Easy	39.8%	ArrayBinary Search
34	Search for a Range	Medium	31.4%	ArrayBinary Search
33	Search in Rotated Sorted Array	Medium	32.1%	ArrayBinary Search
29	Divide Two Integers	Medium	15.9%	MathBinary Search
91	Decode Ways	Medium	19.9%	StringDynamic Programming
95	Unique Binary Search Trees II	Medium	31.7%	Dynamic ProgrammingTree
17	Letter Combinations of a Phone Number	Medium	35.1%	StringBacktracking
22	Generate Parentheses	Medium	45.9%	StringBacktracking
37	Sudoku Solver	Hard	30.8%	Hash TableBacktracking
39	Combination Sum	Medium	39.5%	ArrayBacktracking
40	Combination Sum II	Medium	34.4%	ArrayBacktracking
44	Wildcard Matching	Hard	20.4%	StringDynamic ProgrammingBacktrackingGreedy
46	Permutations	Medium	44.8%	Backtracking
47	Permutations II	Medium	33.4%	Backtracking
51	N-Queens	Hard	31.7%	Backtracking
52	N-Queens II	Hard	45.5%	Backtracking
60	Permutation Sequence	Medium	28.9%	MathBacktracking
77	Combinations	Medium	40.2%	Backtracking
78	Subsets	Medium	41.8%	ArrayBacktrackingBit Manipulation
79	Word Search	Medium	27.2%	ArrayBacktracking
89	Gray Code	Medium	41.6%	Backtracking
90	Subsets II	Medium	36.9%	ArrayBacktracking
93	Restore IP Addresses	Medium	27.7%	StringBacktracking
473	Matchsticks to Square	Medium	35.5%	Depth-first Search
126	Word Ladder II	Hard	14.4%	ArrayStringBacktrackingBreadth-first Search
118	Pascal's Triangle	Easy	39.0%	Array
119	Pascal's Triangle II	Easy	37.3%	Array
120	Triangle	Medium	34.1%	ArrayDynamic Programming
121	Best Time to Buy and Sell Stock	Easy	41.7%	ArrayDynamic Programming
122	Best Time to Buy and Sell Stock II	Easy	47.4%	ArrayGreedy
123	Best Time to Buy and Sell Stock III	Hard	29.6%	ArrayDynamic Programming
126	Word Ladder II	Hard	14.4%	ArrayStringBacktrackingBreadth-first Search
117	Populating Next Right Pointers in Each Node II	Medium	33.8%	TreeDepth-first Search
124	Binary Tree Maximum Path Sum	Hard	26.4%	TreeDepth-first Search
125	Valid Palindrome	Easy	26.5%	Two PointersString
117	Populating Next Right Pointers in Each Node II	Medium	33.8%	TreeDepth-first Search
124	Binary Tree Maximum Path Sum	Hard	26.4%	TreeDepth-first Search
123	Best Time to Buy and Sell Stock III	Hard	29.6%	ArrayDynamic Programming
121	Best Time to Buy and Sell Stock	Easy	41.7%	ArrayDynamic Programming
120	Triangle	Medium	34.1%	ArrayDynamic Programming
337	House Robber III	Medium	43.9%	TreeDepth-first Search
153	Find Minimum in Rotated Sorted Array	Medium	40.2%	ArrayBinary Search
140	Word Break II	Hard	23.6%	Dynamic ProgrammingBacktracking
128	Longest Consecutive Sequence	Hard	37.3%	ArrayUnion Find
152	Maximum Product Subarray	Medium	26.0%	ArrayDynamic Programming
153	Find Minimum in Rotated Sorted Array	Medium	40.2%	ArrayBinary Search
132	Palindrome Partitioning II	Hard	24.4%	Dynamic Programming
139	Word Break	Medium	30.4%	Dynamic Programming
140	Word Break II	Hard	23.6%	Dynamic ProgrammingBacktracking
152	Maximum Product Subarray	Medium	26.0%	ArrayDynamic Programming
149	Max Points on a Line	Hard	15.3%	Hash TableMath
138	Copy List with Random Pointer	Medium	26.1%	Hash TableLinked List
136	Single Number	Easy	54.8%	Hash TableBit Manipulation
129	Sum Root to Leaf Numbers	Medium	37.0%	TreeDepth-first Search
133	Clone Graph	Medium	25.1%	Depth-first SearchBreadth-first SearchGraph
131	Palindrome Partitioning	Medium	34.0%	Backtracking
141	Linked List Cycle	Easy	35.3%	Linked ListTwo Pointers
142	Linked List Cycle II	Medium	30.9%	Linked ListTwo Pointers
146	LRU Cache	Hard	18.4%	Design
129	Sum Root to Leaf Numbers	Medium	37.0%	TreeDepth-first Search
144	Binary Tree Preorder Traversal	Medium	45.5%	StackTree
145	Binary Tree Postorder Traversal	Hard	40.6%	StackTree
149	Max Points on a Line	Hard	15.3%	Hash TableMath
213	House Robber II	Medium	34.2%	Dynamic Programming
462	Minimum Moves to Equal Array Elements II	Medium	51.8%	Math
441	Arranging Coins	Easy	36.3%	MathBinary Search
423	Reconstruct Original Digits from English	Medium	44.5%	Math
415	Add Strings	Easy	41.5%	Math
413	Arithmetic Slices	Medium	54.6%	MathDynamic Programming
400	Nth Digit	Easy	30.0%	Math
397	Integer Replacement	Medium	30.3%	MathBit Manipulation
396	Rotate Function	Medium	33.3%	Math
372	Super Pow	Medium	34.5%	Math
368	Largest Divisible Subset	Medium	33.8%	MathDynamic Programming
367	Valid Perfect Square	Easy	38.4%	MathBinary Search
365	Water and Jug Problem	Medium	27.7%	Math
360	Sort Transformed Array	Medium	44.2%	MathTwo Pointers
357	Count Numbers with Unique Digits	Medium	46.1%	MathDynamic ProgrammingBacktracking
356	Line Reflection	Medium	30.1%	Hash TableMath
343	Integer Break	Medium	46.2%	MathDynamic Programming
335	Self Crossing	Hard	25.6%	Math
326	Power of Three	Easy	40.4%	Math
319	Bulb Switcher	Medium	42.6%	MathBrainteaser
313	Super Ugly Number	Medium	37.9%	MathHeap
296	Best Meeting Point	Hard	51.9%	MathSort
279	Perfect Squares	Medium	37.3%	MathDynamic ProgrammingBreadth-first Search
273	Integer to English Words	Hard	22.3%	MathString
268	Missing Number	Easy	44.3%	ArrayMathBit Manipulation
264	Ugly Number II	Medium	32.9%	MathDynamic ProgrammingHeap
263	Ugly Number	Easy	39.4%	Math
258	Add Digits	Easy	51.4%	Math
248	Strobogrammatic Number III	Hard	32.1%	MathRecursion
247	Strobogrammatic Number II	Medium	40.3%	MathRecursion
246	Strobogrammatic Number	Easy	40.0%	Hash TableMath
233	Number of Digit One	Hard	28.6%	Math
231	Power of Two	Easy	40.3%	MathBit Manipulation
224	Basic Calculator	Hard	27.5%	MathStack
223	Rectangle Area	Medium	33.2%	Math
204	Count Primes	Easy	26.7%	Hash TableMath
202	Happy Number	Easy	40.9%	Hash TableMath
172	Factorial Trailing Zeroes	Easy	36.3%	Math
171	Excel Sheet Column Number	Easy	47.6%	Math
168	Excel Sheet Column Title	Easy	26.5%	Math
166	Fraction to Recurring Decimal	Medium	17.7%	Hash TableMath
454	4Sum II	Medium	47.2%	Hash TableBinary Search
167	Two Sum II - Input array is sorted	Easy	47.1%	ArrayTwo PointersBinary Search
174	Dungeon Game	Hard	23.9%	Binary SearchDynamic Programming
209	Minimum Size Subarray Sum	Medium	31.2%	ArrayTwo PointersBinary Search
222	Count Complete Tree Nodes	Medium	27.6%	Binary SearchTree
230	Kth Smallest Element in a BST	Medium	44.2%	Binary SearchTree
240	Search a 2D Matrix II	Medium	38.7%	Binary SearchDivide and Conquer
270	Closest Binary Search Tree Value	Easy	39.9%	Binary SearchTree
275	H-Index II	Medium	34.6%	Binary Search
278	First Bad Version	Easy	25.6%	Binary Search
287	Find the Duplicate Number	Medium	43.7%	ArrayTwo PointersBinary Search
256	Paint House	Easy	46.2%	Dynamic Programming
264	Ugly Number II	Medium	32.9%	MathDynamic ProgrammingHeap
265	Paint House II	Hard	38.0%	Dynamic Programming
276	Paint Fence	Easy	34.6%	Dynamic Programming
279	Perfect Squares	Medium	37.3%	MathDynamic ProgrammingBreadth-first Search
300	Longest Increasing Subsequence	Medium	38.6%	Binary SearchDynamic Programming
303	Range Sum Query - Immutable	Easy	30.4%	Dynamic Programming
304	Range Sum Query 2D - Immutable	Medium	25.8%	Dynamic Programming
309	Best Time to Buy and Sell Stock with Cooldown	Medium	41.1%	Dynamic Programming
312	Burst Balloons	Hard	43.0%	Divide and ConquerDynamic Programming
321	Create Maximum Number	Hard	24.6%	Dynamic ProgrammingGreedy
322	Coin Change	Medium	26.7%	Dynamic Programming
338	Counting Bits	Medium	61.6%	Dynamic ProgrammingBit Manipulation
343	Integer Break	Medium	46.2%	MathDynamic Programming
351	Android Unlock Patterns	Medium	44.1%	Dynamic ProgrammingBacktracking
354	Russian Doll Envelopes	Hard	32.4%	Binary SearchDynamic Programming
357	Count Numbers with Unique Digits	Medium	46.1%	MathDynamic ProgrammingBacktracking
361	Bomb Enemy	Medium	39.1%	Dynamic Programming
363	Max Sum of Rectangle No Larger Than K	Hard	33.3%	Binary SearchDynamic ProgrammingQueue
368	Largest Divisible Subset	Medium	33.8%	MathDynamic Programming
375	Guess Number Higher or Lower II	Medium	35.8%	Dynamic ProgrammingMinimax
376	Wiggle Subsequence	Medium	35.9%	Dynamic ProgrammingGreedy
377	Combination Sum IV	Medium	42.2%	Dynamic Programming
451	Sort Characters By Frequency	Medium	51.1%	Hash TableHeap
447	Number of Boomerangs	Easy	45.4%	Hash Table
438	Find All Anagrams in a String	Easy	33.7%	Hash Table
409	Longest Palindrome	Easy	45.4%	Hash Table
389	Find the Difference	Easy	50.9%	Hash TableBit Manipulation
381	Insert Delete GetRandom O(1) - Duplicates allowed	Hard	29.0%	ArrayHash TableDesign
380	Insert Delete GetRandom O(1)	Medium	39.3%	ArrayHash TableDesign
359	Logger Rate Limiter	Easy	59.9%	Hash TableDesign
358	Rearrange String k Distance Apart	Hard	31.6%	Hash TableHeapGreedy
450	Delete Node in a BST	Medium	37.1%	Tree
449	Serialize and Deserialize BST	Medium	42.5%	Tree
437	Path Sum III	Easy	39.9%	Tree
404	Sum of Left Leaves	Easy	47.2%	Tree
366	Find Leaves of Binary Tree	Medium	60.1%	TreeDepth-first Search
337	House Robber III	Medium	43.9%	TreeDepth-first Search
333	Largest BST Subtree	Medium	30.5%	Tree
298	Binary Tree Longest Consecutive Sequence	Medium	41.2%	Tree
297	Serialize and Deserialize Binary Tree	Hard	33.8%	TreeDesign
285	Inorder Successor in BST	Medium	36.2%	Tree
272	Closest Binary Search Tree Value II	Hard	39.3%	StackTree
270	Closest Binary Search Tree Value	Easy	39.9%	Binary SearchTree
257	Binary Tree Paths	Easy	39.3%	TreeDepth-first Search
255	Verify Preorder Sequence in Binary Search Tree	Medium	40.5%	StackTree
250	Count Univalue Subtrees	Medium	42.5%	Tree
236	Lowest Common Ancestor of a Binary Tree	Medium	30.0%	Tree
235	Lowest Common Ancestor of a Binary Search Tree	Easy	39.3%	Tree
230	Kth Smallest Element in a BST	Medium	44.2%	Binary SearchTree
226	Invert Binary Tree	Easy	52.3%	Tree
222	Count Complete Tree Nodes	Medium	27.6%	Binary SearchTree
199	Binary Tree Right Side View	Medium	41.5%	TreeDepth-first SearchBreadth-first Search
173	Binary Search Tree Iterator	Medium	42.0%	StackTreeDesign
156	Binary Tree Upside Down	Medium	44.9%	Tree
356	Line Reflection	Medium	30.1%	Hash TableMath
355	Design Twitter	Medium	25.6%	Hash TableHeapDesign
350	Intersection of Two Arrays II	Easy	44.7%	Hash TableTwo PointersBinary SearchSort
401	Binary Watch	Easy	44.8%	BacktrackingBit Manipulation
357	Count Numbers with Unique Digits	Medium	46.1%	MathDynamic ProgrammingBacktracking
300	Longest Increasing Subsequence	Medium	38.6%	Binary SearchDynamic Programming
302	Smallest Rectangle Enclosing Black Pixels	Hard	45.7%	Binary Search
349	Intersection of Two Arrays	Easy	47.5%	Hash TableTwo PointersBinary SearchSort
350	Intersection of Two Arrays II	Easy	44.7%	Hash TableTwo PointersBinary SearchSort
354	Russian Doll Envelopes	Hard	32.4%	Binary SearchDynamic Programming
363	Max Sum of Rectangle No Larger Than K	Hard	33.3%	Binary SearchDynamic ProgrammingQueue
367	Valid Perfect Square	Easy	38.4%	MathBinary Search
349	Intersection of Two Arrays	Easy	47.5%	Hash TableTwo PointersBinary SearchSort
374	Guess Number Higher or Lower	Easy	35.7%	Binary Search
378	Kth Smallest Element in a Sorted Matrix	Medium	45.0%	Binary SearchHeap
392	Is Subsequence	Medium	44.6%	Binary SearchDynamic ProgrammingGreedy
410	Split Array Largest Sum	Hard	38.2%	Binary SearchDynamic Programming
436	Find Right Interval	Medium	41.4%	Binary Search
441	Arranging Coins	Easy	36.3%	MathBinary Search
454	4Sum II	Medium	47.2%	Hash TableBinary Search
347	Top K Frequent Elements	Medium	48.5%	Hash TableHeap
340	Longest Substring with At Most K Distinct Characters	Hard	39.0%	Hash TableString
336	Palindrome Pairs	Hard	26.4%	Hash TableStringTrie
155	Min Stack	Easy	29.3%	StackDesign
170	Two Sum III - Data structure design	Easy	25.0%	Hash TableDesign
403	Frog Jump	Hard	32.4%	Dynamic Programming
410	Split Array Largest Sum	Hard	38.2%	Binary SearchDynamic Programming
325	Maximum Size Subarray Sum Equals k	Medium	42.8%	Hash Table
314	Binary Tree Vertical Order Traversal	Medium	37.1%	Hash Table
311	Sparse Matrix Multiplication	Medium	51.3%	Hash Table
360	Sort Transformed Array	Medium	44.2%	MathTwo Pointers
350	Intersection of Two Arrays II	Easy	44.7%	Hash TableTwo PointersBinary SearchSort
349	Intersection of Two Arrays	Easy	47.5%	Hash TableTwo PointersBinary SearchSort
345	Reverse Vowels of a String	Easy	38.6%	Two PointersString
344	Reverse String	Easy	59.5%	Two PointersString
287	Find the Duplicate Number	Medium	43.7%	ArrayTwo PointersBinary Search
283	Move Zeroes	Easy	50.4%	ArrayTwo Pointers
259	3Sum Smaller	Medium	41.6%	ArrayTwo Pointers
234	Palindrome Linked List	Easy	33.0%	Linked ListTwo Pointers
209	Minimum Size Subarray Sum	Medium	31.2%	ArrayTwo PointersBinary Search
167	Two Sum II - Input array is sorted	Easy	47.1%	ArrayTwo PointersBinary Search
159	Longest Substring with At Most Two Distinct Characters	Hard	41.6%	Hash TableTwo PointersString
299	Bulls and Cows	Medium	35.2%	Hash Table
162	Find Peak Element	Medium	37.9%	ArrayBinary Search
351	Android Unlock Patterns	Medium	44.1%	Dynamic ProgrammingBacktracking
173	Binary Search Tree Iterator	Medium	42.0%	StackTreeDesign
208	Implement Trie (Prefix Tree)	Medium	29.1%	DesignTrie
211	Add and Search Word - Data structure design	Medium	23.7%	BacktrackingDesignTrie
225	Implement Stack using Queues	Easy	33.3%	StackDesign
232	Implement Queue using Stacks	Easy	37.2%	StackDesign
244	Shortest Word Distance II	Medium	38.9%	Hash TableDesign
251	Flatten 2D Vector	Medium	40.8%	Design
281	Zigzag Iterator	Medium	51.1%	Design
284	Peeking Iterator	Medium	35.5%	Design
288	Unique Word Abbreviation	Medium	17.0%	Hash TableDesign
295	Find Median from Data Stream	Hard	27.5%	HeapDesign
297	Serialize and Deserialize Binary Tree	Hard	33.8%	TreeDesign
341	Flatten Nested List Iterator	Medium	42.1%	StackDesign
346	Moving Average from Data Stream	Easy	59.1%	DesignQueue
348	Design Tic-Tac-Toe	Medium	45.9%	Design
353	Design Snake Game	Medium	26.7%	DesignQueue
413	Arithmetic Slices	Medium	54.6%	MathDynamic Programming
416	Partition Equal Subset Sum	Medium	39.3%	Dynamic Programming
418	Sentence Screen Fitting	Medium	27.8%	Dynamic Programming
446	Arithmetic Slices II - Subsequence	Hard	27.2%	Dynamic Programming
211	Add and Search Word - Data structure design	Medium	23.7%	BacktrackingDesignTrie
212	Word Search II	Hard	23.7%	BacktrackingTrie
216	Combination Sum III	Medium	45.8%	ArrayBacktracking
254	Factor Combinations	Medium	43.0%	Backtracking
267	Palindrome Permutation II	Medium	31.9%	Backtracking
291	Word Pattern II	Hard	38.0%	Backtracking
425	Word Squares	Hard	43.1%	BacktrackingTrie
411	Minimum Unique Word Abbreviation	Hard	33.0%	BacktrackingBit Manipulation
154	Find Minimum in Rotated Sorted Array II	Hard	37.4%	ArrayBinary Search
162	Find Peak Element	Medium	37.9%	ArrayBinary Search
163	Missing Ranges	Medium	23.9%	Array
167	Two Sum II - Input array is sorted	Easy	47.1%	ArrayTwo PointersBinary Search
169	Majority Element	Easy	47.0%	ArrayDivide and ConquerBit Manipulation
189	Rotate Array	Easy	24.9%	Array
209	Minimum Size Subarray Sum	Medium	31.2%	ArrayTwo PointersBinary Search
216	Combination Sum III	Medium	45.8%	ArrayBacktracking
217	Contains Duplicate	Easy	46.1%	ArrayHash Table
219	Contains Duplicate II	Easy	32.6%	ArrayHash Table
228	Summary Ranges	Medium	30.5%	Array
229	Majority Element II	Medium	28.7%	Array
238	Product of Array Except Self	Medium	49.6%	Array
243	Shortest Word Distance	Easy	52.8%	Array
245	Shortest Word Distance III	Medium	50.6%	Array
439	Ternary Expression Parser	Medium	51.1%	StackDepth-first Search
417	Pacific Atlantic Water Flow	Medium	33.8%	Depth-first SearchBreadth-first Search
394	Decode String	Medium	41.5%	StackDepth-first Search
366	Find Leaves of Binary Tree	Medium	60.1%	TreeDepth-first Search
364	Nested List Weight Sum II	Medium	52.9%	Depth-first Search
339	Nested List Weight Sum	Easy	62.4%	Depth-first Search
154	Find Minimum in Rotated Sorted Array II	Hard	37.4%	ArrayBinary Search
332	Reconstruct Itinerary	Medium	29.4%	Depth-first SearchGraph
329	Longest Increasing Path in a Matrix	Hard	36.7%	Depth-first SearchTopological SortMemoization
323	Number of Connected Components in an Undirected Graph	Medium	48.2%	Depth-first SearchBreadth-first SearchUnion FindGraph
301	Remove Invalid Parentheses	Hard	35.3%	Depth-first SearchBreadth-first Search
261	Graph Valid Tree	Medium	38.0%	Depth-first SearchBreadth-first SearchUnion FindGraph
257	Binary Tree Paths	Easy	39.3%	TreeDepth-first Search
210	Course Schedule II	Medium	28.7%	Depth-first SearchBreadth-first SearchGraphTopological Sort
207	Course Schedule	Medium	32.6%	Depth-first SearchBreadth-first SearchGraphTopological Sort
200	Number of Islands	Medium	35.2%	Depth-first SearchBreadth-first SearchUnion Find
199	Binary Tree Right Side View	Medium	41.5%	TreeDepth-first SearchBreadth-first Search
221	Maximal Square	Medium	29.4%	Dynamic Programming
453	Minimum Moves to Equal Array Elements	Easy	47.5%	Math
320	Generalized Abbreviation	Medium	45.2%	BacktrackingBit Manipulation
294	Flip Game II	Medium	46.5%	Backtracking
355	Design Twitter	Medium	25.6%	Hash TableHeapDesign
359	Logger Rate Limiter	Easy	59.9%	Hash TableDesign
362	Design Hit Counter	Medium	54.3%	Design
379	Design Phone Directory	Medium	33.6%	Linked ListDesign
380	Insert Delete GetRandom O(1)	Medium	39.3%	ArrayHash TableDesign
381	Insert Delete GetRandom O(1) - Duplicates allowed	Hard	29.0%	ArrayHash TableDesign
432	All O`one Data Structure	Hard	28.2%	Design
460	LFU Cache	Hard	24.3%	Design
198	House Robber	Easy	39.3%	Dynamic Programming
188	Best Time to Buy and Sell Stock IV	Hard	24.4%	Dynamic Programming
174	Dungeon Game	Hard	23.9%	Binary SearchDynamic Programming
159	Longest Substring with At Most Two Distinct Characters	Hard	41.6%	Hash TableTwo PointersString
166	Fraction to Recurring Decimal	Medium	17.7%	Hash TableMath
170	Two Sum III - Data structure design	Easy	25.0%	Hash TableDesign
187	Repeated DNA Sequences	Medium	32.0%	Hash TableBit Manipulation
259	3Sum Smaller	Medium	41.6%	ArrayTwo Pointers
268	Missing Number	Easy	44.3%	ArrayMathBit Manipulation
277	Find the Celebrity	Medium	35.6%	Array
280	Wiggle Sort	Medium	57.6%	ArraySort
283	Move Zeroes	Easy	50.4%	ArrayTwo Pointers
287	Find the Duplicate Number	Medium	43.7%	ArrayTwo PointersBinary Search
289	Game of Life	Medium	37.1%	Array
370	Range Addition	Medium	56.2%	Array
202	Happy Number	Easy	40.9%	Hash TableMath
204	Count Primes	Easy	26.7%	Hash TableMath
205	Isomorphic Strings	Easy	34.1%	Hash Table
217	Contains Duplicate	Easy	46.1%	ArrayHash Table
219	Contains Duplicate II	Easy	32.6%	ArrayHash Table
242	Valid Anagram	Easy	46.7%	Hash TableSort
244	Shortest Word Distance II	Medium	38.9%	Hash TableDesign
246	Strobogrammatic Number	Easy	40.0%	Hash TableMath
249	Group Shifted Strings	Medium	42.2%	Hash TableString
266	Palindrome Permutation	Easy	57.3%	Hash Table
274	H-Index	Medium	33.4%	Hash TableSort
288	Unique Word Abbreviation	Medium	17.0%	Hash TableDesign
290	Word Pattern	Easy	33.2%	Hash Table
380	Insert Delete GetRandom O(1)	Medium	39.3%	ArrayHash TableDesign
381	Insert Delete GetRandom O(1) - Duplicates allowed	Hard	29.0%	ArrayHash TableDesign
414	Third Maximum Number	Easy	27.9%	Array
442	Find All Duplicates in an Array	Medium	56.1%	Array
448	Find All Numbers Disappeared in an Array	Easy	51.2%	Array
567	Permutation in String	Medium	36.6%	Two Pointers
485	Max Consecutive Ones	Easy	53.9%	Array
463	Island Perimeter	Easy	57.3%	Hash Table
469	Convex Polygon	Medium	32.9%	Math
483	Smallest Good Base	Hard	33.3%	MathBinary Search
475	Heaters	Easy	29.6%	Binary Search
483	Smallest Good Base	Hard	33.3%	MathBinary Search
464	Can I Win	Medium	25.0%	Dynamic ProgrammingMinimax
466	Count The Repetitions	Hard	28.0%	Dynamic Programming
467	Unique Substrings in Wraparound String	Medium	32.9%	Dynamic Programming
471	Encode String with Shortest Length	Hard	42.5%	Dynamic Programming
472	Concatenated Words	Hard	30.3%	Dynamic ProgrammingDepth-first SearchTrie
474	Ones and Zeroes	Medium	38.9%	Dynamic Programming
472	Concatenated Words	Hard	30.3%	Dynamic ProgrammingDepth-first SearchTrie
639	Decode Ways II	Hard	23.6%	Dynamic Programming
486	Predict the Winner	Medium	45.1%	Dynamic ProgrammingMinimax
638	Shopping Offers	Medium	42.9%	Dynamic ProgrammingDepth-first Search
488	Zuma Game	Hard	37.5%	Depth-first Search
487	Max Consecutive Ones II	Medium	45.5%	Two Pointers
621	Task Scheduler	Medium	42.1%	ArrayGreedyQueue
494	Target Sum	Medium	43.4%	Dynamic ProgrammingDepth-first Search
490	The Maze	Medium	43.2%	Depth-first SearchBreadth-first Search
491	Increasing Subsequences	Medium	38.8%	Depth-first Search
494	Target Sum	Medium	43.4%	Dynamic ProgrammingDepth-first Search
642	Design Search Autocomplete System	Hard	30.0%	DesignTrie
515	Find Largest Value in Each Tree Row	Medium	55.0%	TreeDepth-first SearchBreadth-first Search
499	The Maze III	Hard	32.7%	Depth-first SearchBreadth-first Search
505	The Maze II	Medium	37.7%	Depth-first SearchBreadth-first Search
495	Teemo Attacking	Medium	51.5%	Array
508	Most Frequent Subtree Sum	Medium	52.3%	Hash TableTree
500	Keyboard Row	Easy	59.7%	Hash Table
515	Find Largest Value in Each Tree Row	Medium	55.0%	TreeDepth-first SearchBreadth-first Search
514	Freedom Trail	Hard	39.2%	Divide and ConquerDynamic ProgrammingDepth-first Search
514	Freedom Trail	Hard	39.2%	Divide and ConquerDynamic ProgrammingDepth-first Search
513	Find Bottom Left Tree Value	Medium	56.1%	TreeDepth-first SearchBreadth-first Search
508	Most Frequent Subtree Sum	Medium	52.3%	Hash TableTree
501	Find Mode in Binary Search Tree	Easy	37.7%	Tree
507	Perfect Number	Easy	33.8%	Math
513	Find Bottom Left Tree Value	Medium	56.1%	TreeDepth-first SearchBreadth-first Search
645	Set Mismatch	Easy	40.3%	Hash TableMath
535	Encode and Decode TinyURL	Medium	74.2%	Hash TableMath
524	Longest Word in Dictionary through Deleting	Medium	42.9%	Two PointersSort
532	K-diff Pairs in an Array	Easy	28.2%	ArrayTwo Pointers
523	Continuous Subarray Sum	Medium	23.0%	MathDynamic Programming
529	Minesweeper	Medium	49.5%	Depth-first SearchBreadth-first Search
531	Lonely Pixel I	Medium	55.3%	ArrayDepth-first Search
535	Encode and Decode TinyURL	Medium	74.2%	Hash TableMath
517	Super Washing Machines	Hard	36.5%	MathDynamic Programming
533	Lonely Pixel II	Medium	44.2%	ArrayDepth-first Search
533	Lonely Pixel II	Medium	44.2%	ArrayDepth-first Search
523	Continuous Subarray Sum	Medium	23.0%	MathDynamic Programming
517	Super Washing Machines	Hard	36.5%	MathDynamic Programming
516	Longest Palindromic Subsequence	Medium	42.7%	Dynamic Programming
526	Beautiful Arrangement	Medium	54.5%	Backtracking
525	Contiguous Array	Medium	40.5%	Hash Table
531	Lonely Pixel I	Medium	55.3%	ArrayDepth-first Search
532	K-diff Pairs in an Array	Easy	28.2%	ArrayTwo Pointers
645	Set Mismatch	Easy	40.3%	Hash TableMath
545	Boundary of Binary Tree	Medium	31.7%	Tree
543	Diameter of Binary Tree	Easy	44.4%	Tree
538	Convert BST to Greater Tree	Easy	49.4%	Tree
537	Complex Number Multiplication	Medium	64.0%	MathString
542	01 Matrix	Medium	33.3%	Depth-first SearchBreadth-first Search
536	Construct Binary Tree from String	Medium	42.6%	StringTree
632	Smallest Range	Hard	42.4%	Hash TableTwo PointersString
554	Brick Wall	Medium	45.7%	Hash Table
549	Binary Tree Longest Consecutive Sequence II	Medium	41.3%	Tree
547	Friend Circles	Medium	49.2%	Depth-first SearchUnion Find
552	Student Attendance Record II	Hard	31.4%	Dynamic Programming
548	Split Array with Equal Sum	Medium	36.8%	Array
546	Remove Boxes	Hard	34.0%	Dynamic ProgrammingDepth-first Search
553	Optimal Division	Medium	55.1%	MathString
546	Remove Boxes	Hard	34.0%	Dynamic ProgrammingDepth-first Search
690	Employee Importance	Easy	55.5%	Hash TableDepth-first SearchBreadth-first Search
594	Longest Harmonious Subsequence	Easy	41.1%	Hash Table
588	Design In-Memory File System	Hard	34.7%	Design
560	Subarray Sum Equals K	Medium	40.2%	ArrayMap
563	Binary Tree Tilt	Easy	47.1%	Tree
593	Valid Square	Medium	40.0%	Math
592	Fraction Addition and Subtraction	Medium	46.4%	Math
573	Squirrel Simulation	Medium	52.3%	Math
582	Kill Process	Medium	49.5%	TreeQueue
566	Reshape the Matrix	Easy	58.5%	Array
581	Shortest Unsorted Continuous Subarray	Easy	29.5%	Array
575	Distribute Candies	Easy	58.7%	Hash Table
576	Out of Boundary Paths	Medium	30.9%	Dynamic ProgrammingDepth-first Search
568	Maximum Vacation Days	Hard	39.9%	Dynamic Programming
576	Out of Boundary Paths	Medium	30.9%	Dynamic ProgrammingDepth-first Search
562	Longest Line of Consecutive One in Matrix	Medium	40.6%	Array
561	Array Partition I	Easy	66.8%	Array
572	Subtree of Another Tree	Easy	40.8%	Tree
663	Equal Tree Partition	Medium	36.6%	Tree
605	Can Place Flowers	Easy	30.0%	Array
604	Design Compressed String Iterator	Easy	32.4%	Design
599	Minimum Index Sum of Two Lists	Easy	46.3%	Hash Table
598	Range Addition II	Easy	48.2%	Math
600	Non-negative Integers without Consecutive Ones	Hard	30.4%	Dynamic Programming
671	Second Minimum Node In a Binary Tree	Easy	41.9%	Tree
635	Design Log Storage System	Medium	48.4%	StringDesign
628	Maximum Product of Three Numbers	Easy	45.0%	ArrayMath
631	Design Excel Sum Formula	Hard	26.6%	Design
629	K Inverse Pairs Array	Hard	26.7%	Dynamic Programming
606	Construct String from Binary Tree	Easy	49.8%	StringTree
609	Find Duplicate File in System	Medium	52.5%	Hash TableString
624	Maximum Distance in Arrays	Easy	34.1%	ArrayHash Table
611	Valid Triangle Number	Medium	41.7%	Array
617	Merge Two Binary Trees	Easy	67.9%	Tree
634	Find the Derangement of An Array	Medium	33.8%	Math
633	Sum of Square Numbers	Easy	32.2%	Math
628	Maximum Product of Three Numbers	Easy	45.0%	ArrayMath
625	Minimum Factorization	Medium	30.7%	MathRecursion
624	Maximum Distance in Arrays	Easy	34.1%	ArrayHash Table
632	Smallest Range	Hard	42.4%	Hash TableTwo PointersString
623	Add One Row to Tree	Medium	46.6%	Tree
665	Non-decreasing Array	Easy	21.3%	Array
646	Maximum Length of Pair Chain	Medium	47.7%	Dynamic Programming
637	Average of Levels in Binary Tree	Easy	55.8%	Tree
643	Maximum Average Subarray I	Easy	37.7%	Array
638	Shopping Offers	Medium	42.9%	Dynamic ProgrammingDepth-first Search
640	Solve the Equation	Medium	39.0%	Math
644	Maximum Average Subarray II	Hard	22.1%	ArrayBinary Search
644	Maximum Average Subarray II	Hard	22.1%	ArrayBinary Search
689	Maximum Sum of 3 Non-Overlapping Subarrays	Hard	42.9%	ArrayDynamic Programming
691	Stickers to Spell Word	Hard	31.7%	Dynamic ProgrammingBacktracking
673	Number of Longest Increasing Subsequence	Medium	30.9%	Dynamic Programming
652	Find Duplicate Subtrees	Medium	34.9%	Tree
653	Two Sum IV - Input is a BST	Easy	50.7%	Tree
654	Maximum Binary Tree	Medium	70.2%	Tree
655	Print Binary Tree	Medium	50.6%	Tree
676	Implement Magic Dictionary	Medium	50.0%	Hash TableTrie
647	Palindromic Substrings	Medium	55.8%	StringDynamic Programming
666	Path Sum IV	Medium	49.4%	Tree
669	Trim a Binary Search Tree	Easy	58.4%	Tree
662	Maximum Width of Binary Tree	Medium	37.7%	Tree
684	Redundant Connection	Medium	35.8%	TreeUnion FindGraph
685	Redundant Connection II	Hard	28.8%	TreeDepth-first SearchUnion FindGraph
687	Longest Univalue Path	Easy	32.3%	TreeRecursion
648	Replace Words	Medium	47.7%	Hash TableTrie
650	2 Keys Keyboard	Medium	44.1%	Dynamic Programming
651	4 Keys Keyboard	Medium	47.9%	MathDynamic ProgrammingGreedy
656	Coin Path	Hard	24.5%	Dynamic Programming
668	Kth Smallest Number in Multiplication Table	Hard	37.0%	Binary Search
667	Beautiful Arrangement II	Medium	51.6%	Array
690	Employee Importance	Easy	55.5%	Hash TableDepth-first SearchBreadth-first Search
661	Image Smoother	Easy	45.8%	Array
688	Knight Probability in Chessboard	Medium	38.3%	Dynamic Programming
685	Redundant Connection II	Hard	28.8%	TreeDepth-first SearchUnion FindGraph
679	24 Game	Hard	38.5%	Depth-first Search
664	Strange Printer	Hard	31.4%	Dynamic ProgrammingDepth-first Search
664	Strange Printer	Hard	31.4%	Dynamic ProgrammingDepth-first Search
670	Maximum Swap	Medium	38.4%	ArrayMath
651	4 Keys Keyboard	Medium	47.9%	MathDynamic ProgrammingGreedy
660	Remove 9	Hard	47.1%	Math
670	Maximum Swap	Medium	38.4%	ArrayMath
672	Bulb Switcher II	Medium	48.1%	Math
674	Longest Continuous Increasing Subsequence	Easy	43.0%	Array
691	Stickers to Spell Word	Hard	31.7%	Dynamic ProgrammingBacktracking
689	Maximum Sum of 3 Non-Overlapping Subarrays	Hard	42.9%	ArrayDynamic Programming
683	K Empty Slots	Hard	37.2%	ArrayBinary Search Tree
658	Find K Closest Elements	Medium	35.7%	Binary Search
692	Top K Frequent Words	Medium	41.1%	Hash TableHeapTrie
694	Number of Distinct Islands	Medium	43.5%	Hash TableDepth-first Search
694	Number of Distinct Islands	Medium	43.5%	Hash TableDepth-first Search
695	Max Area of Island	Easy	53.3%	ArrayDepth-first Search
695	Max Area of Island	Easy	53.3%	ArrayDepth-first Search
697	Degree of an Array	Easy	48.9%	Array
698	Partition to K Equal Sum Subsets	Medium	34.7%	Dynamic ProgrammingRecursion
711	Number of Distinct Islands II	Hard	26.0%	Hash TableDepth-first Search
711	Number of Distinct Islands II	Hard	26.0%	Hash TableDepth-first Search

Tag:binary-search

ID	Title	Difficulty	Acceptance	Tags
300	Longest Increasing Subsequence	Medium	38.6%	Binary SearchDynamic Programming
392	Is Subsequence	Medium	44.6%	Binary SearchDynamic ProgrammingGreedy
1	Two Sum	Easy	35.6%	ArrayHash Table
4	Median of Two Sorted Arrays	Hard	22.1%	ArrayBinary SearchDivide and Conquer
3	Longest Substring Without Repeating Characters	Medium	24.4%	Hash TableTwo PointersString
2	Add Two Numbers	Medium	28.0%	Linked ListMath
7	Reverse Integer	Easy	24.5%	Math
8	String to Integer (atoi)	Medium	14.0%	MathString
9	Palindrome Number	Easy	35.5%	Math
10	Regular Expression Matching	Hard	24.2%	StringDynamic ProgrammingBacktracking
4	Median of Two Sorted Arrays	Hard	22.1%	ArrayBinary SearchDivide and Conquer
1	Two Sum	Easy	35.6%	ArrayHash Table
3	Longest Substring Without Repeating Characters	Medium	24.4%	Hash TableTwo PointersString
107	Binary Tree Level Order Traversal II	Easy	40.8%	TreeBreadth-first Search
42	Trapping Rain Water	Hard	37.0%	ArrayTwo PointersStack
45	Jump Game II	Hard	26.2%	ArrayGreedy
48	Rotate Image	Medium	39.5%	Array
53	Maximum Subarray	Easy	39.8%	ArrayDivide and ConquerDynamic Programming
54	Spiral Matrix	Medium	26.4%	Array
55	Jump Game	Medium	29.5%	ArrayGreedy
56	Merge Intervals	Medium	30.7%	ArraySort
57	Insert Interval	Hard	28.1%	ArraySort
59	Spiral Matrix II	Medium	40.1%	Array
62	Unique Paths	Medium	41.7%	ArrayDynamic Programming
63	Unique Paths II	Medium	31.9%	ArrayDynamic Programming
64	Minimum Path Sum	Medium	38.9%	ArrayDynamic Programming
66	Plus One	Easy	38.9%	ArrayMath
73	Set Matrix Zeroes	Medium	36.1%	Array
74	Search a 2D Matrix	Medium	34.9%	ArrayBinary Search
75	Sort Colors	Medium	38.3%	ArrayTwo PointersSort
78	Subsets	Medium	41.8%	ArrayBacktrackingBit Manipulation
79	Word Search	Medium	27.2%	ArrayBacktracking
80	Remove Duplicates from Sorted Array II	Medium	36.3%	ArrayTwo Pointers
81	Search in Rotated Sorted Array II	Medium	32.7%	ArrayBinary Search
84	Largest Rectangle in Histogram	Hard	27.0%	ArrayStack
85	Maximal Rectangle	Hard	28.5%	ArrayHash TableDynamic ProgrammingStack
88	Merge Sorted Array	Easy	32.1%	ArrayTwo Pointers
90	Subsets II	Medium	36.9%	ArrayBacktracking
105	Construct Binary Tree from Preorder and Inorder Traversal	Medium	32.6%	ArrayTreeDepth-first Search
106	Construct Binary Tree from Inorder and Postorder Traversal	Medium	32.4%	ArrayTreeDepth-first Search
41	First Missing Positive	Hard	25.6%	Array
40	Combination Sum II	Medium	34.4%	ArrayBacktracking
39	Combination Sum	Medium	39.5%	ArrayBacktracking
35	Search Insert Position	Easy	39.8%	ArrayBinary Search
34	Search for a Range	Medium	31.4%	ArrayBinary Search
33	Search in Rotated Sorted Array	Medium	32.1%	ArrayBinary Search
31	Next Permutation	Medium	28.8%	Array
27	Remove Element	Easy	39.6%	ArrayTwo Pointers
26	Remove Duplicates from Sorted Array	Easy	35.4%	ArrayTwo Pointers
18	4Sum	Medium	27.0%	ArrayHash TableTwo Pointers
16	3Sum Closest	Medium	31.3%	ArrayTwo Pointers
15	3Sum	Medium	21.8%	ArrayTwo Pointers
11	Container With Most Water	Medium	36.8%	ArrayTwo Pointers
98	Validate Binary Search Tree	Medium	23.6%	TreeDepth-first Search
99	Recover Binary Search Tree	Hard	30.2%	TreeDepth-first Search
100	Same Tree	Easy	46.8%	TreeDepth-first Search
101	Symmetric Tree	Easy	39.2%	TreeDepth-first SearchBreadth-first Search
104	Maximum Depth of Binary Tree	Easy	53.1%	TreeDepth-first Search
105	Construct Binary Tree from Preorder and Inorder Traversal	Medium	32.6%	ArrayTreeDepth-first Search
106	Construct Binary Tree from Inorder and Postorder Traversal	Medium	32.4%	ArrayTreeDepth-first Search
94	Binary Tree Inorder Traversal	Medium	47.4%	Hash TableStackTree
85	Maximal Rectangle	Hard	28.5%	ArrayHash TableDynamic ProgrammingStack
76	Minimum Window Substring	Hard	25.9%	Hash TableTwo PointersString
49	Group Anagrams	Medium	35.9%	Hash TableString
37	Sudoku Solver	Hard	30.8%	Hash TableBacktracking
36	Valid Sudoku	Medium	36.3%	Hash Table
30	Substring with Concatenation of All Words	Hard	22.0%	Hash TableTwo PointersString
18	4Sum	Medium	27.0%	ArrayHash TableTwo Pointers
32	Longest Valid Parentheses	Hard	23.1%	StringDynamic Programming
44	Wildcard Matching	Hard	20.4%	StringDynamic ProgrammingBacktrackingGreedy
53	Maximum Subarray	Easy	39.8%	ArrayDivide and ConquerDynamic Programming
62	Unique Paths	Medium	41.7%	ArrayDynamic Programming
63	Unique Paths II	Medium	31.9%	ArrayDynamic Programming
64	Minimum Path Sum	Medium	38.9%	ArrayDynamic Programming
70	Climbing Stairs	Easy	40.3%	Dynamic Programming
108	Convert Sorted Array to Binary Search Tree	Easy	42.5%	TreeDepth-first Search
109	Convert Sorted List to Binary Search Tree	Medium	34.4%	Linked ListDepth-first Search
110	Balanced Binary Tree	Easy	37.8%	TreeDepth-first Search
111	Minimum Depth of Binary Tree	Easy	33.3%	TreeDepth-first SearchBreadth-first Search
112	Path Sum	Easy	34.2%	TreeDepth-first Search
113	Path Sum II	Medium	34.3%	TreeDepth-first Search
114	Flatten Binary Tree to Linked List	Medium	35.5%	TreeDepth-first Search
116	Populating Next Right Pointers in Each Node	Medium	36.9%	TreeDepth-first Search
11	Container With Most Water	Medium	36.8%	ArrayTwo Pointers
15	3Sum	Medium	21.8%	ArrayTwo Pointers
16	3Sum Closest	Medium	31.3%	ArrayTwo Pointers
18	4Sum	Medium	27.0%	ArrayHash TableTwo Pointers
19	Remove Nth Node From End of List	Medium	33.8%	Linked ListTwo Pointers
26	Remove Duplicates from Sorted Array	Easy	35.4%	ArrayTwo Pointers
27	Remove Element	Easy	39.6%	ArrayTwo Pointers
28	Implement strStr()	Easy	28.4%	Two PointersString
30	Substring with Concatenation of All Words	Hard	22.0%	Hash TableTwo PointersString
42	Trapping Rain Water	Hard	37.0%	ArrayTwo PointersStack
61	Rotate List	Medium	24.3%	Linked ListTwo Pointers
75	Sort Colors	Medium	38.3%	ArrayTwo PointersSort
76	Minimum Window Substring	Hard	25.9%	Hash TableTwo PointersString
80	Remove Duplicates from Sorted Array II	Medium	36.3%	ArrayTwo Pointers
86	Partition List	Medium	33.0%	Linked ListTwo Pointers
88	Merge Sorted Array	Easy	32.1%	ArrayTwo Pointers
94	Binary Tree Inorder Traversal	Medium	47.4%	Hash TableStackTree
95	Unique Binary Search Trees II	Medium	31.7%	Dynamic ProgrammingTree
96	Unique Binary Search Trees	Medium	41.3%	Dynamic ProgrammingTree
72	Edit Distance	Hard	32.0%	StringDynamic Programming
85	Maximal Rectangle	Hard	28.5%	ArrayHash TableDynamic ProgrammingStack
87	Scramble String	Hard	29.4%	StringDynamic Programming
98	Validate Binary Search Tree	Medium	23.6%	TreeDepth-first Search
99	Recover Binary Search Tree	Hard	30.2%	TreeDepth-first Search
100	Same Tree	Easy	46.8%	TreeDepth-first Search
101	Symmetric Tree	Easy	39.2%	TreeDepth-first SearchBreadth-first Search
102	Binary Tree Level Order Traversal	Medium	40.6%	TreeBreadth-first Search
103	Binary Tree Zigzag Level Order Traversal	Medium	35.2%	StackTreeBreadth-first Search
104	Maximum Depth of Binary Tree	Easy	53.1%	TreeDepth-first Search
105	Construct Binary Tree from Preorder and Inorder Traversal	Medium	32.6%	ArrayTreeDepth-first Search
106	Construct Binary Tree from Inorder and Postorder Traversal	Medium	32.4%	ArrayTreeDepth-first Search
108	Convert Sorted Array to Binary Search Tree	Easy	42.5%	TreeDepth-first Search
110	Balanced Binary Tree	Easy	37.8%	TreeDepth-first Search
111	Minimum Depth of Binary Tree	Easy	33.3%	TreeDepth-first SearchBreadth-first Search
112	Path Sum	Easy	34.2%	TreeDepth-first Search
113	Path Sum II	Medium	34.3%	TreeDepth-first Search
114	Flatten Binary Tree to Linked List	Medium	35.5%	TreeDepth-first Search
10	Regular Expression Matching	Hard	24.2%	StringDynamic ProgrammingBacktracking
12	Integer to Roman	Medium	45.3%	MathString
13	Roman to Integer	Easy	46.4%	MathString
29	Divide Two Integers	Medium	15.9%	MathBinary Search
43	Multiply Strings	Medium	27.5%	MathString
50	Pow(x, n)	Medium	26.1%	MathBinary Search
60	Permutation Sequence	Medium	28.9%	MathBacktracking
65	Valid Number	Hard	12.8%	MathString
66	Plus One	Easy	38.9%	ArrayMath
67	Add Binary	Easy	33.0%	MathString
69	Sqrt(x)	Easy	28.0%	MathBinary Search
115	Distinct Subsequences	Hard	31.7%	StringDynamic Programming
97	Interleaving String	Hard	24.8%	StringDynamic Programming
96	Unique Binary Search Trees	Medium	41.3%	Dynamic ProgrammingTree
81	Search in Rotated Sorted Array II	Medium	32.7%	ArrayBinary Search
74	Search a 2D Matrix	Medium	34.9%	ArrayBinary Search
69	Sqrt(x)	Easy	28.0%	MathBinary Search
50	Pow(x, n)	Medium	26.1%	MathBinary Search
35	Search Insert Position	Easy	39.8%	ArrayBinary Search
34	Search for a Range	Medium	31.4%	ArrayBinary Search
33	Search in Rotated Sorted Array	Medium	32.1%	ArrayBinary Search
29	Divide Two Integers	Medium	15.9%	MathBinary Search
91	Decode Ways	Medium	19.9%	StringDynamic Programming
95	Unique Binary Search Trees II	Medium	31.7%	Dynamic ProgrammingTree
17	Letter Combinations of a Phone Number	Medium	35.1%	StringBacktracking
22	Generate Parentheses	Medium	45.9%	StringBacktracking
37	Sudoku Solver	Hard	30.8%	Hash TableBacktracking
39	Combination Sum	Medium	39.5%	ArrayBacktracking
40	Combination Sum II	Medium	34.4%	ArrayBacktracking
44	Wildcard Matching	Hard	20.4%	StringDynamic ProgrammingBacktrackingGreedy
46	Permutations	Medium	44.8%	Backtracking
47	Permutations II	Medium	33.4%	Backtracking
51	N-Queens	Hard	31.7%	Backtracking
52	N-Queens II	Hard	45.5%	Backtracking
60	Permutation Sequence	Medium	28.9%	MathBacktracking
77	Combinations	Medium	40.2%	Backtracking
78	Subsets	Medium	41.8%	ArrayBacktrackingBit Manipulation
79	Word Search	Medium	27.2%	ArrayBacktracking
89	Gray Code	Medium	41.6%	Backtracking
90	Subsets II	Medium	36.9%	ArrayBacktracking
93	Restore IP Addresses	Medium	27.7%	StringBacktracking
381	Insert Delete GetRandom O(1) - Duplicates allowed	Hard	29.0%	ArrayHash TableDesign
126	Word Ladder II	Hard	14.4%	ArrayStringBacktrackingBreadth-first Search
118	Pascal's Triangle	Easy	39.0%	Array
119	Pascal's Triangle II	Easy	37.3%	Array
120	Triangle	Medium	34.1%	ArrayDynamic Programming
121	Best Time to Buy and Sell Stock	Easy	41.7%	ArrayDynamic Programming
122	Best Time to Buy and Sell Stock II	Easy	47.4%	ArrayGreedy
123	Best Time to Buy and Sell Stock III	Hard	29.6%	ArrayDynamic Programming
126	Word Ladder II	Hard	14.4%	ArrayStringBacktrackingBreadth-first Search
117	Populating Next Right Pointers in Each Node II	Medium	33.8%	TreeDepth-first Search
124	Binary Tree Maximum Path Sum	Hard	26.4%	TreeDepth-first Search
125	Valid Palindrome	Easy	26.5%	Two PointersString
117	Populating Next Right Pointers in Each Node II	Medium	33.8%	TreeDepth-first Search
124	Binary Tree Maximum Path Sum	Hard	26.4%	TreeDepth-first Search
123	Best Time to Buy and Sell Stock III	Hard	29.6%	ArrayDynamic Programming
121	Best Time to Buy and Sell Stock	Easy	41.7%	ArrayDynamic Programming
120	Triangle	Medium	34.1%	ArrayDynamic Programming
337	House Robber III	Medium	43.9%	TreeDepth-first Search
153	Find Minimum in Rotated Sorted Array	Medium	40.2%	ArrayBinary Search
140	Word Break II	Hard	23.6%	Dynamic ProgrammingBacktracking
128	Longest Consecutive Sequence	Hard	37.3%	ArrayUnion Find
152	Maximum Product Subarray	Medium	26.0%	ArrayDynamic Programming
153	Find Minimum in Rotated Sorted Array	Medium	40.2%	ArrayBinary Search
132	Palindrome Partitioning II	Hard	24.4%	Dynamic Programming
139	Word Break	Medium	30.4%	Dynamic Programming
140	Word Break II	Hard	23.6%	Dynamic ProgrammingBacktracking
152	Maximum Product Subarray	Medium	26.0%	ArrayDynamic Programming
149	Max Points on a Line	Hard	15.3%	Hash TableMath
138	Copy List with Random Pointer	Medium	26.1%	Hash TableLinked List
136	Single Number	Easy	54.8%	Hash TableBit Manipulation
129	Sum Root to Leaf Numbers	Medium	37.0%	TreeDepth-first Search
133	Clone Graph	Medium	25.1%	Depth-first SearchBreadth-first SearchGraph
131	Palindrome Partitioning	Medium	34.0%	Backtracking
141	Linked List Cycle	Easy	35.3%	Linked ListTwo Pointers
142	Linked List Cycle II	Medium	30.9%	Linked ListTwo Pointers
146	LRU Cache	Hard	18.4%	Design
129	Sum Root to Leaf Numbers	Medium	37.0%	TreeDepth-first Search
144	Binary Tree Preorder Traversal	Medium	45.5%	StackTree
145	Binary Tree Postorder Traversal	Hard	40.6%	StackTree
149	Max Points on a Line	Hard	15.3%	Hash TableMath
213	House Robber II	Medium	34.2%	Dynamic Programming
380	Insert Delete GetRandom O(1)	Medium	39.3%	ArrayHash TableDesign
290	Word Pattern	Easy	33.2%	Hash Table
288	Unique Word Abbreviation	Medium	17.0%	Hash TableDesign
274	H-Index	Medium	33.4%	Hash TableSort
266	Palindrome Permutation	Easy	57.3%	Hash Table
249	Group Shifted Strings	Medium	42.2%	Hash TableString
246	Strobogrammatic Number	Easy	40.0%	Hash TableMath
244	Shortest Word Distance II	Medium	38.9%	Hash TableDesign
372	Super Pow	Medium	34.5%	Math
368	Largest Divisible Subset	Medium	33.8%	MathDynamic Programming
367	Valid Perfect Square	Easy	38.4%	MathBinary Search
365	Water and Jug Problem	Medium	27.7%	Math
360	Sort Transformed Array	Medium	44.2%	MathTwo Pointers
357	Count Numbers with Unique Digits	Medium	46.1%	MathDynamic ProgrammingBacktracking
356	Line Reflection	Medium	30.1%	Hash TableMath
343	Integer Break	Medium	46.2%	MathDynamic Programming
335	Self Crossing	Hard	25.6%	Math
326	Power of Three	Easy	40.4%	Math
319	Bulb Switcher	Medium	42.6%	MathBrainteaser
313	Super Ugly Number	Medium	37.9%	MathHeap
296	Best Meeting Point	Hard	51.9%	MathSort
279	Perfect Squares	Medium	37.3%	MathDynamic ProgrammingBreadth-first Search
273	Integer to English Words	Hard	22.3%	MathString
268	Missing Number	Easy	44.3%	ArrayMathBit Manipulation
264	Ugly Number II	Medium	32.9%	MathDynamic ProgrammingHeap
263	Ugly Number	Easy	39.4%	Math
258	Add Digits	Easy	51.4%	Math
248	Strobogrammatic Number III	Hard	32.1%	MathRecursion
247	Strobogrammatic Number II	Medium	40.3%	MathRecursion
246	Strobogrammatic Number	Easy	40.0%	Hash TableMath
233	Number of Digit One	Hard	28.6%	Math
231	Power of Two	Easy	40.3%	MathBit Manipulation
224	Basic Calculator	Hard	27.5%	MathStack
223	Rectangle Area	Medium	33.2%	Math
204	Count Primes	Easy	26.7%	Hash TableMath
202	Happy Number	Easy	40.9%	Hash TableMath
172	Factorial Trailing Zeroes	Easy	36.3%	Math
171	Excel Sheet Column Number	Easy	47.6%	Math
168	Excel Sheet Column Title	Easy	26.5%	Math
166	Fraction to Recurring Decimal	Medium	17.7%	Hash TableMath
242	Valid Anagram	Easy	46.7%	Hash TableSort
167	Two Sum II - Input array is sorted	Easy	47.1%	ArrayTwo PointersBinary Search
174	Dungeon Game	Hard	23.9%	Binary SearchDynamic Programming
209	Minimum Size Subarray Sum	Medium	31.2%	ArrayTwo PointersBinary Search
222	Count Complete Tree Nodes	Medium	27.6%	Binary SearchTree
230	Kth Smallest Element in a BST	Medium	44.2%	Binary SearchTree
240	Search a 2D Matrix II	Medium	38.7%	Binary SearchDivide and Conquer
270	Closest Binary Search Tree Value	Easy	39.9%	Binary SearchTree
275	H-Index II	Medium	34.6%	Binary Search
278	First Bad Version	Easy	25.6%	Binary Search
287	Find the Duplicate Number	Medium	43.7%	ArrayTwo PointersBinary Search
256	Paint House	Easy	46.2%	Dynamic Programming
264	Ugly Number II	Medium	32.9%	MathDynamic ProgrammingHeap
265	Paint House II	Hard	38.0%	Dynamic Programming
276	Paint Fence	Easy	34.6%	Dynamic Programming
279	Perfect Squares	Medium	37.3%	MathDynamic ProgrammingBreadth-first Search
300	Longest Increasing Subsequence	Medium	38.6%	Binary SearchDynamic Programming
303	Range Sum Query - Immutable	Easy	30.4%	Dynamic Programming
304	Range Sum Query 2D - Immutable	Medium	25.8%	Dynamic Programming
309	Best Time to Buy and Sell Stock with Cooldown	Medium	41.1%	Dynamic Programming
312	Burst Balloons	Hard	43.0%	Divide and ConquerDynamic Programming
321	Create Maximum Number	Hard	24.6%	Dynamic ProgrammingGreedy
322	Coin Change	Medium	26.7%	Dynamic Programming
338	Counting Bits	Medium	61.6%	Dynamic ProgrammingBit Manipulation
343	Integer Break	Medium	46.2%	MathDynamic Programming
351	Android Unlock Patterns	Medium	44.1%	Dynamic ProgrammingBacktracking
354	Russian Doll Envelopes	Hard	32.4%	Binary SearchDynamic Programming
357	Count Numbers with Unique Digits	Medium	46.1%	MathDynamic ProgrammingBacktracking
361	Bomb Enemy	Medium	39.1%	Dynamic Programming
363	Max Sum of Rectangle No Larger Than K	Hard	33.3%	Binary SearchDynamic ProgrammingQueue
368	Largest Divisible Subset	Medium	33.8%	MathDynamic Programming
375	Guess Number Higher or Lower II	Medium	35.8%	Dynamic ProgrammingMinimax
376	Wiggle Subsequence	Medium	35.9%	Dynamic ProgrammingGreedy
377	Combination Sum IV	Medium	42.2%	Dynamic Programming
219	Contains Duplicate II	Easy	32.6%	ArrayHash Table
217	Contains Duplicate	Easy	46.1%	ArrayHash Table
205	Isomorphic Strings	Easy	34.1%	Hash Table
204	Count Primes	Easy	26.7%	Hash TableMath
389	Find the Difference	Easy	50.9%	Hash TableBit Manipulation
381	Insert Delete GetRandom O(1) - Duplicates allowed	Hard	29.0%	ArrayHash TableDesign
380	Insert Delete GetRandom O(1)	Medium	39.3%	ArrayHash TableDesign
359	Logger Rate Limiter	Easy	59.9%	Hash TableDesign
358	Rearrange String k Distance Apart	Hard	31.6%	Hash TableHeapGreedy
202	Happy Number	Easy	40.9%	Hash TableMath
370	Range Addition	Medium	56.2%	Array
289	Game of Life	Medium	37.1%	Array
287	Find the Duplicate Number	Medium	43.7%	ArrayTwo PointersBinary Search
366	Find Leaves of Binary Tree	Medium	60.1%	TreeDepth-first Search
337	House Robber III	Medium	43.9%	TreeDepth-first Search
333	Largest BST Subtree	Medium	30.5%	Tree
298	Binary Tree Longest Consecutive Sequence	Medium	41.2%	Tree
297	Serialize and Deserialize Binary Tree	Hard	33.8%	TreeDesign
285	Inorder Successor in BST	Medium	36.2%	Tree
272	Closest Binary Search Tree Value II	Hard	39.3%	StackTree
270	Closest Binary Search Tree Value	Easy	39.9%	Binary SearchTree
257	Binary Tree Paths	Easy	39.3%	TreeDepth-first Search
255	Verify Preorder Sequence in Binary Search Tree	Medium	40.5%	StackTree
250	Count Univalue Subtrees	Medium	42.5%	Tree
236	Lowest Common Ancestor of a Binary Tree	Medium	30.0%	Tree
235	Lowest Common Ancestor of a Binary Search Tree	Easy	39.3%	Tree
230	Kth Smallest Element in a BST	Medium	44.2%	Binary SearchTree
226	Invert Binary Tree	Easy	52.3%	Tree
222	Count Complete Tree Nodes	Medium	27.6%	Binary SearchTree
199	Binary Tree Right Side View	Medium	41.5%	TreeDepth-first SearchBreadth-first Search
173	Binary Search Tree Iterator	Medium	42.0%	StackTreeDesign
156	Binary Tree Upside Down	Medium	44.9%	Tree
356	Line Reflection	Medium	30.1%	Hash TableMath
355	Design Twitter	Medium	25.6%	Hash TableHeapDesign
350	Intersection of Two Arrays II	Easy	44.7%	Hash TableTwo PointersBinary SearchSort
283	Move Zeroes	Easy	50.4%	ArrayTwo Pointers
357	Count Numbers with Unique Digits	Medium	46.1%	MathDynamic ProgrammingBacktracking
116	Populating Next Right Pointers in Each Node	Medium	36.9%	TreeDepth-first Search
302	Smallest Rectangle Enclosing Black Pixels	Hard	45.7%	Binary Search
349	Intersection of Two Arrays	Easy	47.5%	Hash TableTwo PointersBinary SearchSort
350	Intersection of Two Arrays II	Easy	44.7%	Hash TableTwo PointersBinary SearchSort
354	Russian Doll Envelopes	Hard	32.4%	Binary SearchDynamic Programming
363	Max Sum of Rectangle No Larger Than K	Hard	33.3%	Binary SearchDynamic ProgrammingQueue
367	Valid Perfect Square	Easy	38.4%	MathBinary Search
349	Intersection of Two Arrays	Easy	47.5%	Hash TableTwo PointersBinary SearchSort
374	Guess Number Higher or Lower	Easy	35.7%	Binary Search
378	Kth Smallest Element in a Sorted Matrix	Medium	45.0%	Binary SearchHeap
392	Is Subsequence	Medium	44.6%	Binary SearchDynamic ProgrammingGreedy
280	Wiggle Sort	Medium	57.6%	ArraySort
277	Find the Celebrity	Medium	35.6%	Array
268	Missing Number	Easy	44.3%	ArrayMathBit Manipulation
259	3Sum Smaller	Medium	41.6%	ArrayTwo Pointers
347	Top K Frequent Elements	Medium	48.5%	Hash TableHeap
340	Longest Substring with At Most K Distinct Characters	Hard	39.0%	Hash TableString
336	Palindrome Pairs	Hard	26.4%	Hash TableStringTrie
155	Min Stack	Easy	29.3%	StackDesign
170	Two Sum III - Data structure design	Easy	25.0%	Hash TableDesign
187	Repeated DNA Sequences	Medium	32.0%	Hash TableBit Manipulation
170	Two Sum III - Data structure design	Easy	25.0%	Hash TableDesign
325	Maximum Size Subarray Sum Equals k	Medium	42.8%	Hash Table
314	Binary Tree Vertical Order Traversal	Medium	37.1%	Hash Table
311	Sparse Matrix Multiplication	Medium	51.3%	Hash Table
360	Sort Transformed Array	Medium	44.2%	MathTwo Pointers
350	Intersection of Two Arrays II	Easy	44.7%	Hash TableTwo PointersBinary SearchSort
349	Intersection of Two Arrays	Easy	47.5%	Hash TableTwo PointersBinary SearchSort
345	Reverse Vowels of a String	Easy	38.6%	Two PointersString
344	Reverse String	Easy	59.5%	Two PointersString
287	Find the Duplicate Number	Medium	43.7%	ArrayTwo PointersBinary Search
283	Move Zeroes	Easy	50.4%	ArrayTwo Pointers
259	3Sum Smaller	Medium	41.6%	ArrayTwo Pointers
234	Palindrome Linked List	Easy	33.0%	Linked ListTwo Pointers
209	Minimum Size Subarray Sum	Medium	31.2%	ArrayTwo PointersBinary Search
167	Two Sum II - Input array is sorted	Easy	47.1%	ArrayTwo PointersBinary Search
159	Longest Substring with At Most Two Distinct Characters	Hard	41.6%	Hash TableTwo PointersString
299	Bulls and Cows	Medium	35.2%	Hash Table
162	Find Peak Element	Medium	37.9%	ArrayBinary Search
351	Android Unlock Patterns	Medium	44.1%	Dynamic ProgrammingBacktracking
173	Binary Search Tree Iterator	Medium	42.0%	StackTreeDesign
208	Implement Trie (Prefix Tree)	Medium	29.1%	DesignTrie
211	Add and Search Word - Data structure design	Medium	23.7%	BacktrackingDesignTrie
225	Implement Stack using Queues	Easy	33.3%	StackDesign
232	Implement Queue using Stacks	Easy	37.2%	StackDesign
244	Shortest Word Distance II	Medium	38.9%	Hash TableDesign
251	Flatten 2D Vector	Medium	40.8%	Design
281	Zigzag Iterator	Medium	51.1%	Design
284	Peeking Iterator	Medium	35.5%	Design
288	Unique Word Abbreviation	Medium	17.0%	Hash TableDesign
295	Find Median from Data Stream	Hard	27.5%	HeapDesign
297	Serialize and Deserialize Binary Tree	Hard	33.8%	TreeDesign
341	Flatten Nested List Iterator	Medium	42.1%	StackDesign
346	Moving Average from Data Stream	Easy	59.1%	DesignQueue
348	Design Tic-Tac-Toe	Medium	45.9%	Design
353	Design Snake Game	Medium	26.7%	DesignQueue
166	Fraction to Recurring Decimal	Medium	17.7%	Hash TableMath
159	Longest Substring with At Most Two Distinct Characters	Hard	41.6%	Hash TableTwo PointersString
174	Dungeon Game	Hard	23.9%	Binary SearchDynamic Programming
188	Best Time to Buy and Sell Stock IV	Hard	24.4%	Dynamic Programming
211	Add and Search Word - Data structure design	Medium	23.7%	BacktrackingDesignTrie
212	Word Search II	Hard	23.7%	BacktrackingTrie
216	Combination Sum III	Medium	45.8%	ArrayBacktracking
254	Factor Combinations	Medium	43.0%	Backtracking
267	Palindrome Permutation II	Medium	31.9%	Backtracking
291	Word Pattern II	Hard	38.0%	Backtracking
198	House Robber	Easy	39.3%	Dynamic Programming
381	Insert Delete GetRandom O(1) - Duplicates allowed	Hard	29.0%	ArrayHash TableDesign
154	Find Minimum in Rotated Sorted Array II	Hard	37.4%	ArrayBinary Search
162	Find Peak Element	Medium	37.9%	ArrayBinary Search
163	Missing Ranges	Medium	23.9%	Array
167	Two Sum II - Input array is sorted	Easy	47.1%	ArrayTwo PointersBinary Search
169	Majority Element	Easy	47.0%	ArrayDivide and ConquerBit Manipulation
189	Rotate Array	Easy	24.9%	Array
209	Minimum Size Subarray Sum	Medium	31.2%	ArrayTwo PointersBinary Search
216	Combination Sum III	Medium	45.8%	ArrayBacktracking
217	Contains Duplicate	Easy	46.1%	ArrayHash Table
219	Contains Duplicate II	Easy	32.6%	ArrayHash Table
228	Summary Ranges	Medium	30.5%	Array
229	Majority Element II	Medium	28.7%	Array
238	Product of Array Except Self	Medium	49.6%	Array
243	Shortest Word Distance	Easy	52.8%	Array
245	Shortest Word Distance III	Medium	50.6%	Array
380	Insert Delete GetRandom O(1)	Medium	39.3%	ArrayHash TableDesign
379	Design Phone Directory	Medium	33.6%	Linked ListDesign
362	Design Hit Counter	Medium	54.3%	Design
366	Find Leaves of Binary Tree	Medium	60.1%	TreeDepth-first Search
364	Nested List Weight Sum II	Medium	52.9%	Depth-first Search
339	Nested List Weight Sum	Easy	62.4%	Depth-first Search
154	Find Minimum in Rotated Sorted Array II	Hard	37.4%	ArrayBinary Search
332	Reconstruct Itinerary	Medium	29.4%	Depth-first SearchGraph
329	Longest Increasing Path in a Matrix	Hard	36.7%	Depth-first SearchTopological SortMemoization
323	Number of Connected Components in an Undirected Graph	Medium	48.2%	Depth-first SearchBreadth-first SearchUnion FindGraph
301	Remove Invalid Parentheses	Hard	35.3%	Depth-first SearchBreadth-first Search
261	Graph Valid Tree	Medium	38.0%	Depth-first SearchBreadth-first SearchUnion FindGraph
257	Binary Tree Paths	Easy	39.3%	TreeDepth-first Search
210	Course Schedule II	Medium	28.7%	Depth-first SearchBreadth-first SearchGraphTopological Sort
207	Course Schedule	Medium	32.6%	Depth-first SearchBreadth-first SearchGraphTopological Sort
200	Number of Islands	Medium	35.2%	Depth-first SearchBreadth-first SearchUnion Find
199	Binary Tree Right Side View	Medium	41.5%	TreeDepth-first SearchBreadth-first Search
221	Maximal Square	Medium	29.4%	Dynamic Programming
359	Logger Rate Limiter	Easy	59.9%	Hash TableDesign
320	Generalized Abbreviation	Medium	45.2%	BacktrackingBit Manipulation
294	Flip Game II	Medium	46.5%	Backtracking
355	Design Twitter	Medium	25.6%	Hash TableHeapDesign
632	Smallest Range	Hard	42.4%	Hash TableTwo PointersString
453	Minimum Moves to Equal Array Elements	Easy	47.5%	Math
417	Pacific Atlantic Water Flow	Medium	33.8%	Depth-first SearchBreadth-first Search
439	Ternary Expression Parser	Medium	51.1%	StackDepth-first Search
411	Minimum Unique Word Abbreviation	Hard	33.0%	BacktrackingBit Manipulation
432	All O`one Data Structure	Hard	28.2%	Design
394	Decode String	Medium	41.5%	StackDepth-first Search
425	Word Squares	Hard	43.1%	BacktrackingTrie
446	Arithmetic Slices II - Subsequence	Hard	27.2%	Dynamic Programming
418	Sentence Screen Fitting	Medium	27.8%	Dynamic Programming
416	Partition Equal Subset Sum	Medium	39.3%	Dynamic Programming
413	Arithmetic Slices	Medium	54.6%	MathDynamic Programming
410	Split Array Largest Sum	Hard	38.2%	Binary SearchDynamic Programming
403	Frog Jump	Hard	32.4%	Dynamic Programming
448	Find All Numbers Disappeared in an Array	Easy	51.2%	Array
441	Arranging Coins	Easy	36.3%	MathBinary Search
436	Find Right Interval	Medium	41.4%	Binary Search
410	Split Array Largest Sum	Hard	38.2%	Binary SearchDynamic Programming
401	Binary Watch	Easy	44.8%	BacktrackingBit Manipulation
404	Sum of Left Leaves	Easy	47.2%	Tree
437	Path Sum III	Easy	39.9%	Tree
449	Serialize and Deserialize BST	Medium	42.5%	Tree
450	Delete Node in a BST	Medium	37.1%	Tree
409	Longest Palindrome	Easy	45.4%	Hash Table
438	Find All Anagrams in a String	Easy	33.7%	Hash Table
447	Number of Boomerangs	Easy	45.4%	Hash Table
451	Sort Characters By Frequency	Medium	51.1%	Hash TableHeap
442	Find All Duplicates in an Array	Medium	56.1%	Array
396	Rotate Function	Medium	33.3%	Math
397	Integer Replacement	Medium	30.3%	MathBit Manipulation
400	Nth Digit	Easy	30.0%	Math
413	Arithmetic Slices	Medium	54.6%	MathDynamic Programming
415	Add Strings	Easy	41.5%	Math
423	Reconstruct Original Digits from English	Medium	44.5%	Math
441	Arranging Coins	Easy	36.3%	MathBinary Search
414	Third Maximum Number	Easy	27.9%	Array
566	Reshape the Matrix	Easy	58.5%	Array
473	Matchsticks to Square	Medium	35.5%	Depth-first Search
454	4Sum II	Medium	47.2%	Hash TableBinary Search
454	4Sum II	Medium	47.2%	Hash TableBinary Search
462	Minimum Moves to Equal Array Elements II	Medium	51.8%	Math
460	LFU Cache	Hard	24.3%	Design
463	Island Perimeter	Easy	57.3%	Hash Table
469	Convex Polygon	Medium	32.9%	Math
472	Concatenated Words	Hard	30.3%	Dynamic ProgrammingDepth-first SearchTrie
472	Concatenated Words	Hard	30.3%	Dynamic ProgrammingDepth-first SearchTrie
471	Encode String with Shortest Length	Hard	42.5%	Dynamic Programming
464	Can I Win	Medium	25.0%	Dynamic ProgrammingMinimax
466	Count The Repetitions	Hard	28.0%	Dynamic Programming
467	Unique Substrings in Wraparound String	Medium	32.9%	Dynamic Programming
561	Array Partition I	Easy	66.8%	Array
483	Smallest Good Base	Hard	33.3%	MathBinary Search
474	Ones and Zeroes	Medium	38.9%	Dynamic Programming
483	Smallest Good Base	Hard	33.3%	MathBinary Search
475	Heaters	Easy	29.6%	Binary Search
605	Can Place Flowers	Easy	30.0%	Array
486	Predict the Winner	Medium	45.1%	Dynamic ProgrammingMinimax
485	Max Consecutive Ones	Easy	53.9%	Array
604	Design Compressed String Iterator	Easy	32.4%	Design
487	Max Consecutive Ones II	Medium	45.5%	Two Pointers
599	Minimum Index Sum of Two Lists	Easy	46.3%	Hash Table
494	Target Sum	Medium	43.4%	Dynamic ProgrammingDepth-first Search
491	Increasing Subsequences	Medium	38.8%	Depth-first Search
494	Target Sum	Medium	43.4%	Dynamic ProgrammingDepth-first Search
490	The Maze	Medium	43.2%	Depth-first SearchBreadth-first Search
488	Zuma Game	Hard	37.5%	Depth-first Search
671	Second Minimum Node In a Binary Tree	Easy	41.9%	Tree
499	The Maze III	Hard	32.7%	Depth-first SearchBreadth-first Search
495	Teemo Attacking	Medium	51.5%	Array
628	Maximum Product of Three Numbers	Easy	45.0%	ArrayMath
508	Most Frequent Subtree Sum	Medium	52.3%	Hash TableTree
500	Keyboard Row	Easy	59.7%	Hash Table
505	The Maze II	Medium	37.7%	Depth-first SearchBreadth-first Search
507	Perfect Number	Easy	33.8%	Math
501	Find Mode in Binary Search Tree	Easy	37.7%	Tree
508	Most Frequent Subtree Sum	Medium	52.3%	Hash TableTree
606	Construct String from Binary Tree	Easy	49.8%	StringTree
513	Find Bottom Left Tree Value	Medium	56.1%	TreeDepth-first SearchBreadth-first Search
513	Find Bottom Left Tree Value	Medium	56.1%	TreeDepth-first SearchBreadth-first Search
624	Maximum Distance in Arrays	Easy	34.1%	ArrayHash Table
645	Set Mismatch	Easy	40.3%	Hash TableMath
524	Longest Word in Dictionary through Deleting	Medium	42.9%	Two PointersSort
532	K-diff Pairs in an Array	Easy	28.2%	ArrayTwo Pointers
523	Continuous Subarray Sum	Medium	23.0%	MathDynamic Programming
529	Minesweeper	Medium	49.5%	Depth-first SearchBreadth-first Search
531	Lonely Pixel I	Medium	55.3%	ArrayDepth-first Search
535	Encode and Decode TinyURL	Medium	74.2%	Hash TableMath
517	Super Washing Machines	Hard	36.5%	MathDynamic Programming
533	Lonely Pixel II	Medium	44.2%	ArrayDepth-first Search
533	Lonely Pixel II	Medium	44.2%	ArrayDepth-first Search
523	Continuous Subarray Sum	Medium	23.0%	MathDynamic Programming
517	Super Washing Machines	Hard	36.5%	MathDynamic Programming
516	Longest Palindromic Subsequence	Medium	42.7%	Dynamic Programming
526	Beautiful Arrangement	Medium	54.5%	Backtracking
525	Contiguous Array	Medium	40.5%	Hash Table
531	Lonely Pixel I	Medium	55.3%	ArrayDepth-first Search
532	K-diff Pairs in an Array	Easy	28.2%	ArrayTwo Pointers
645	Set Mismatch	Easy	40.3%	Hash TableMath
545	Boundary of Binary Tree	Medium	31.7%	Tree
543	Diameter of Binary Tree	Easy	44.4%	Tree
538	Convert BST to Greater Tree	Easy	49.4%	Tree
537	Complex Number Multiplication	Medium	64.0%	MathString
542	01 Matrix	Medium	33.3%	Depth-first SearchBreadth-first Search
536	Construct Binary Tree from String	Medium	42.6%	StringTree
515	Find Largest Value in Each Tree Row	Medium	55.0%	TreeDepth-first SearchBreadth-first Search
554	Brick Wall	Medium	45.7%	Hash Table
549	Binary Tree Longest Consecutive Sequence II	Medium	41.3%	Tree
547	Friend Circles	Medium	49.2%	Depth-first SearchUnion Find
552	Student Attendance Record II	Hard	31.4%	Dynamic Programming
548	Split Array with Equal Sum	Medium	36.8%	Array
546	Remove Boxes	Hard	34.0%	Dynamic ProgrammingDepth-first Search
553	Optimal Division	Medium	55.1%	MathString
546	Remove Boxes	Hard	34.0%	Dynamic ProgrammingDepth-first Search
644	Maximum Average Subarray II	Hard	22.1%	ArrayBinary Search
594	Longest Harmonious Subsequence	Easy	41.1%	Hash Table
588	Design In-Memory File System	Hard	34.7%	Design
560	Subarray Sum Equals K	Medium	40.2%	ArrayMap
563	Binary Tree Tilt	Easy	47.1%	Tree
593	Valid Square	Medium	40.0%	Math
592	Fraction Addition and Subtraction	Medium	46.4%	Math
573	Squirrel Simulation	Medium	52.3%	Math
582	Kill Process	Medium	49.5%	TreeQueue
567	Permutation in String	Medium	36.6%	Two Pointers
581	Shortest Unsorted Continuous Subarray	Easy	29.5%	Array
575	Distribute Candies	Easy	58.7%	Hash Table
576	Out of Boundary Paths	Medium	30.9%	Dynamic ProgrammingDepth-first Search
568	Maximum Vacation Days	Hard	39.9%	Dynamic Programming
576	Out of Boundary Paths	Medium	30.9%	Dynamic ProgrammingDepth-first Search
562	Longest Line of Consecutive One in Matrix	Medium	40.6%	Array
639	Decode Ways II	Hard	23.6%	Dynamic Programming
572	Subtree of Another Tree	Easy	40.8%	Tree
644	Maximum Average Subarray II	Hard	22.1%	ArrayBinary Search
638	Shopping Offers	Medium	42.9%	Dynamic ProgrammingDepth-first Search
621	Task Scheduler	Medium	42.1%	ArrayGreedyQueue
642	Design Search Autocomplete System	Hard	30.0%	DesignTrie
598	Range Addition II	Easy	48.2%	Math
600	Non-negative Integers without Consecutive Ones	Hard	30.4%	Dynamic Programming
514	Freedom Trail	Hard	39.2%	Divide and ConquerDynamic ProgrammingDepth-first Search
635	Design Log Storage System	Medium	48.4%	StringDesign
515	Find Largest Value in Each Tree Row	Medium	55.0%	TreeDepth-first SearchBreadth-first Search
631	Design Excel Sum Formula	Hard	26.6%	Design
629	K Inverse Pairs Array	Hard	26.7%	Dynamic Programming
514	Freedom Trail	Hard	39.2%	Divide and ConquerDynamic ProgrammingDepth-first Search
609	Find Duplicate File in System	Medium	52.5%	Hash TableString
535	Encode and Decode TinyURL	Medium	74.2%	Hash TableMath
611	Valid Triangle Number	Medium	41.7%	Array
617	Merge Two Binary Trees	Easy	67.9%	Tree
634	Find the Derangement of An Array	Medium	33.8%	Math
633	Sum of Square Numbers	Easy	32.2%	Math
628	Maximum Product of Three Numbers	Easy	45.0%	ArrayMath
625	Minimum Factorization	Medium	30.7%	MathRecursion
624	Maximum Distance in Arrays	Easy	34.1%	ArrayHash Table
632	Smallest Range	Hard	42.4%	Hash TableTwo PointersString
623	Add One Row to Tree	Medium	46.6%	Tree
640	Solve the Equation	Medium	39.0%	Math
638	Shopping Offers	Medium	42.9%	Dynamic ProgrammingDepth-first Search
637	Average of Levels in Binary Tree	Easy	55.8%	Tree
643	Maximum Average Subarray I	Easy	37.7%	Array
690	Employee Importance	Easy	55.5%	Hash TableDepth-first SearchBreadth-first Search
646	Maximum Length of Pair Chain	Medium	47.7%	Dynamic Programming
661	Image Smoother	Easy	45.8%	Array
663	Equal Tree Partition	Medium	36.6%	Tree
658	Find K Closest Elements	Medium	35.7%	Binary Search
660	Remove 9	Hard	47.1%	Math
651	4 Keys Keyboard	Medium	47.9%	MathDynamic ProgrammingGreedy
652	Find Duplicate Subtrees	Medium	34.9%	Tree
653	Two Sum IV - Input is a BST	Easy	50.7%	Tree
654	Maximum Binary Tree	Medium	70.2%	Tree
655	Print Binary Tree	Medium	50.6%	Tree
656	Coin Path	Hard	24.5%	Dynamic Programming
647	Palindromic Substrings	Medium	55.8%	StringDynamic Programming
651	4 Keys Keyboard	Medium	47.9%	MathDynamic ProgrammingGreedy
650	2 Keys Keyboard	Medium	44.1%	Dynamic Programming
662	Maximum Width of Binary Tree	Medium	37.7%	Tree
648	Replace Words	Medium	47.7%	Hash TableTrie
691	Stickers to Spell Word	Hard	31.7%	Dynamic ProgrammingBacktracking
685	Redundant Connection II	Hard	28.8%	TreeDepth-first SearchUnion FindGraph
684	Redundant Connection	Medium	35.8%	TreeUnion FindGraph
669	Trim a Binary Search Tree	Easy	58.4%	Tree
666	Path Sum IV	Medium	49.4%	Tree
676	Implement Magic Dictionary	Medium	50.0%	Hash TableTrie
668	Kth Smallest Number in Multiplication Table	Hard	37.0%	Binary Search
667	Beautiful Arrangement II	Medium	51.6%	Array
665	Non-decreasing Array	Easy	21.3%	Array
683	K Empty Slots	Hard	37.2%	ArrayBinary Search Tree
674	Longest Continuous Increasing Subsequence	Easy	43.0%	Array
685	Redundant Connection II	Hard	28.8%	TreeDepth-first SearchUnion FindGraph
679	24 Game	Hard	38.5%	Depth-first Search
664	Strange Printer	Hard	31.4%	Dynamic ProgrammingDepth-first Search
664	Strange Printer	Hard	31.4%	Dynamic ProgrammingDepth-first Search
670	Maximum Swap	Medium	38.4%	ArrayMath
673	Number of Longest Increasing Subsequence	Medium	30.9%	Dynamic Programming
672	Bulb Switcher II	Medium	48.1%	Math
670	Maximum Swap	Medium	38.4%	ArrayMath
694	Number of Distinct Islands	Medium	43.5%	Hash TableDepth-first Search
687	Longest Univalue Path	Easy	32.3%	TreeRecursion
694	Number of Distinct Islands	Medium	43.5%	Hash TableDepth-first Search
691	Stickers to Spell Word	Hard	31.7%	Dynamic ProgrammingBacktracking
690	Employee Importance	Easy	55.5%	Hash TableDepth-first SearchBreadth-first Search
689	Maximum Sum of 3 Non-Overlapping Subarrays	Hard	42.9%	ArrayDynamic Programming
689	Maximum Sum of 3 Non-Overlapping Subarrays	Hard	42.9%	ArrayDynamic Programming
688	Knight Probability in Chessboard	Medium	38.3%	Dynamic Programming
692	Top K Frequent Words	Medium	41.1%	Hash TableHeapTrie
695	Max Area of Island	Easy	53.3%	ArrayDepth-first Search
695	Max Area of Island	Easy	53.3%	ArrayDepth-first Search
697	Degree of an Array	Easy	48.9%	Array
698	Partition to K Equal Sum Subsets	Medium	34.7%	Dynamic ProgrammingRecursion
711	Number of Distinct Islands II	Hard	26.0%	Hash TableDepth-first Search
711	Number of Distinct Islands II	Hard	26.0%	Hash TableDepth-first Search

Tag:backtracking

ID	Title	Difficulty	Acceptance	Tags
116	Populating Next Right Pointers in Each Node	Medium	36.9%	TreeDepth-first Search
300	Longest Increasing Subsequence	Medium	38.6%	Binary SearchDynamic Programming
1	Two Sum	Easy	35.6%	ArrayHash Table
4	Median of Two Sorted Arrays	Hard	22.1%	ArrayBinary SearchDivide and Conquer
3	Longest Substring Without Repeating Characters	Medium	24.4%	Hash TableTwo PointersString
2	Add Two Numbers	Medium	28.0%	Linked ListMath
7	Reverse Integer	Easy	24.5%	Math
8	String to Integer (atoi)	Medium	14.0%	MathString
9	Palindrome Number	Easy	35.5%	Math
10	Regular Expression Matching	Hard	24.2%	StringDynamic ProgrammingBacktracking
4	Median of Two Sorted Arrays	Hard	22.1%	ArrayBinary SearchDivide and Conquer
1	Two Sum	Easy	35.6%	ArrayHash Table
3	Longest Substring Without Repeating Characters	Medium	24.4%	Hash TableTwo PointersString
107	Binary Tree Level Order Traversal II	Easy	40.8%	TreeBreadth-first Search
42	Trapping Rain Water	Hard	37.0%	ArrayTwo PointersStack
45	Jump Game II	Hard	26.2%	ArrayGreedy
48	Rotate Image	Medium	39.5%	Array
53	Maximum Subarray	Easy	39.8%	ArrayDivide and ConquerDynamic Programming
54	Spiral Matrix	Medium	26.4%	Array
55	Jump Game	Medium	29.5%	ArrayGreedy
56	Merge Intervals	Medium	30.7%	ArraySort
57	Insert Interval	Hard	28.1%	ArraySort
59	Spiral Matrix II	Medium	40.1%	Array
62	Unique Paths	Medium	41.7%	ArrayDynamic Programming
63	Unique Paths II	Medium	31.9%	ArrayDynamic Programming
64	Minimum Path Sum	Medium	38.9%	ArrayDynamic Programming
66	Plus One	Easy	38.9%	ArrayMath
73	Set Matrix Zeroes	Medium	36.1%	Array
74	Search a 2D Matrix	Medium	34.9%	ArrayBinary Search
75	Sort Colors	Medium	38.3%	ArrayTwo PointersSort
78	Subsets	Medium	41.8%	ArrayBacktrackingBit Manipulation
79	Word Search	Medium	27.2%	ArrayBacktracking
80	Remove Duplicates from Sorted Array II	Medium	36.3%	ArrayTwo Pointers
81	Search in Rotated Sorted Array II	Medium	32.7%	ArrayBinary Search
84	Largest Rectangle in Histogram	Hard	27.0%	ArrayStack
85	Maximal Rectangle	Hard	28.5%	ArrayHash TableDynamic ProgrammingStack
88	Merge Sorted Array	Easy	32.1%	ArrayTwo Pointers
90	Subsets II	Medium	36.9%	ArrayBacktracking
105	Construct Binary Tree from Preorder and Inorder Traversal	Medium	32.6%	ArrayTreeDepth-first Search
106	Construct Binary Tree from Inorder and Postorder Traversal	Medium	32.4%	ArrayTreeDepth-first Search
41	First Missing Positive	Hard	25.6%	Array
40	Combination Sum II	Medium	34.4%	ArrayBacktracking
39	Combination Sum	Medium	39.5%	ArrayBacktracking
35	Search Insert Position	Easy	39.8%	ArrayBinary Search
34	Search for a Range	Medium	31.4%	ArrayBinary Search
33	Search in Rotated Sorted Array	Medium	32.1%	ArrayBinary Search
31	Next Permutation	Medium	28.8%	Array
27	Remove Element	Easy	39.6%	ArrayTwo Pointers
26	Remove Duplicates from Sorted Array	Easy	35.4%	ArrayTwo Pointers
18	4Sum	Medium	27.0%	ArrayHash TableTwo Pointers
16	3Sum Closest	Medium	31.3%	ArrayTwo Pointers
15	3Sum	Medium	21.8%	ArrayTwo Pointers
11	Container With Most Water	Medium	36.8%	ArrayTwo Pointers
98	Validate Binary Search Tree	Medium	23.6%	TreeDepth-first Search
99	Recover Binary Search Tree	Hard	30.2%	TreeDepth-first Search
100	Same Tree	Easy	46.8%	TreeDepth-first Search
101	Symmetric Tree	Easy	39.2%	TreeDepth-first SearchBreadth-first Search
104	Maximum Depth of Binary Tree	Easy	53.1%	TreeDepth-first Search
105	Construct Binary Tree from Preorder and Inorder Traversal	Medium	32.6%	ArrayTreeDepth-first Search
106	Construct Binary Tree from Inorder and Postorder Traversal	Medium	32.4%	ArrayTreeDepth-first Search
94	Binary Tree Inorder Traversal	Medium	47.4%	Hash TableStackTree
85	Maximal Rectangle	Hard	28.5%	ArrayHash TableDynamic ProgrammingStack
76	Minimum Window Substring	Hard	25.9%	Hash TableTwo PointersString
49	Group Anagrams	Medium	35.9%	Hash TableString
37	Sudoku Solver	Hard	30.8%	Hash TableBacktracking
36	Valid Sudoku	Medium	36.3%	Hash Table
30	Substring with Concatenation of All Words	Hard	22.0%	Hash TableTwo PointersString
18	4Sum	Medium	27.0%	ArrayHash TableTwo Pointers
32	Longest Valid Parentheses	Hard	23.1%	StringDynamic Programming
44	Wildcard Matching	Hard	20.4%	StringDynamic ProgrammingBacktrackingGreedy
53	Maximum Subarray	Easy	39.8%	ArrayDivide and ConquerDynamic Programming
62	Unique Paths	Medium	41.7%	ArrayDynamic Programming
63	Unique Paths II	Medium	31.9%	ArrayDynamic Programming
64	Minimum Path Sum	Medium	38.9%	ArrayDynamic Programming
70	Climbing Stairs	Easy	40.3%	Dynamic Programming
108	Convert Sorted Array to Binary Search Tree	Easy	42.5%	TreeDepth-first Search
109	Convert Sorted List to Binary Search Tree	Medium	34.4%	Linked ListDepth-first Search
110	Balanced Binary Tree	Easy	37.8%	TreeDepth-first Search
111	Minimum Depth of Binary Tree	Easy	33.3%	TreeDepth-first SearchBreadth-first Search
112	Path Sum	Easy	34.2%	TreeDepth-first Search
113	Path Sum II	Medium	34.3%	TreeDepth-first Search
114	Flatten Binary Tree to Linked List	Medium	35.5%	TreeDepth-first Search
116	Populating Next Right Pointers in Each Node	Medium	36.9%	TreeDepth-first Search
11	Container With Most Water	Medium	36.8%	ArrayTwo Pointers
15	3Sum	Medium	21.8%	ArrayTwo Pointers
16	3Sum Closest	Medium	31.3%	ArrayTwo Pointers
18	4Sum	Medium	27.0%	ArrayHash TableTwo Pointers
19	Remove Nth Node From End of List	Medium	33.8%	Linked ListTwo Pointers
26	Remove Duplicates from Sorted Array	Easy	35.4%	ArrayTwo Pointers
27	Remove Element	Easy	39.6%	ArrayTwo Pointers
28	Implement strStr()	Easy	28.4%	Two PointersString
30	Substring with Concatenation of All Words	Hard	22.0%	Hash TableTwo PointersString
42	Trapping Rain Water	Hard	37.0%	ArrayTwo PointersStack
61	Rotate List	Medium	24.3%	Linked ListTwo Pointers
75	Sort Colors	Medium	38.3%	ArrayTwo PointersSort
76	Minimum Window Substring	Hard	25.9%	Hash TableTwo PointersString
80	Remove Duplicates from Sorted Array II	Medium	36.3%	ArrayTwo Pointers
86	Partition List	Medium	33.0%	Linked ListTwo Pointers
88	Merge Sorted Array	Easy	32.1%	ArrayTwo Pointers
94	Binary Tree Inorder Traversal	Medium	47.4%	Hash TableStackTree
95	Unique Binary Search Trees II	Medium	31.7%	Dynamic ProgrammingTree
96	Unique Binary Search Trees	Medium	41.3%	Dynamic ProgrammingTree
72	Edit Distance	Hard	32.0%	StringDynamic Programming
85	Maximal Rectangle	Hard	28.5%	ArrayHash TableDynamic ProgrammingStack
87	Scramble String	Hard	29.4%	StringDynamic Programming
98	Validate Binary Search Tree	Medium	23.6%	TreeDepth-first Search
99	Recover Binary Search Tree	Hard	30.2%	TreeDepth-first Search
100	Same Tree	Easy	46.8%	TreeDepth-first Search
101	Symmetric Tree	Easy	39.2%	TreeDepth-first SearchBreadth-first Search
102	Binary Tree Level Order Traversal	Medium	40.6%	TreeBreadth-first Search
103	Binary Tree Zigzag Level Order Traversal	Medium	35.2%	StackTreeBreadth-first Search
104	Maximum Depth of Binary Tree	Easy	53.1%	TreeDepth-first Search
105	Construct Binary Tree from Preorder and Inorder Traversal	Medium	32.6%	ArrayTreeDepth-first Search
106	Construct Binary Tree from Inorder and Postorder Traversal	Medium	32.4%	ArrayTreeDepth-first Search
108	Convert Sorted Array to Binary Search Tree	Easy	42.5%	TreeDepth-first Search
110	Balanced Binary Tree	Easy	37.8%	TreeDepth-first Search
111	Minimum Depth of Binary Tree	Easy	33.3%	TreeDepth-first SearchBreadth-first Search
112	Path Sum	Easy	34.2%	TreeDepth-first Search
113	Path Sum II	Medium	34.3%	TreeDepth-first Search
114	Flatten Binary Tree to Linked List	Medium	35.5%	TreeDepth-first Search
10	Regular Expression Matching	Hard	24.2%	StringDynamic ProgrammingBacktracking
12	Integer to Roman	Medium	45.3%	MathString
13	Roman to Integer	Easy	46.4%	MathString
29	Divide Two Integers	Medium	15.9%	MathBinary Search
43	Multiply Strings	Medium	27.5%	MathString
50	Pow(x, n)	Medium	26.1%	MathBinary Search
60	Permutation Sequence	Medium	28.9%	MathBacktracking
65	Valid Number	Hard	12.8%	MathString
66	Plus One	Easy	38.9%	ArrayMath
67	Add Binary	Easy	33.0%	MathString
69	Sqrt(x)	Easy	28.0%	MathBinary Search
115	Distinct Subsequences	Hard	31.7%	StringDynamic Programming
97	Interleaving String	Hard	24.8%	StringDynamic Programming
96	Unique Binary Search Trees	Medium	41.3%	Dynamic ProgrammingTree
81	Search in Rotated Sorted Array II	Medium	32.7%	ArrayBinary Search
74	Search a 2D Matrix	Medium	34.9%	ArrayBinary Search
69	Sqrt(x)	Easy	28.0%	MathBinary Search
50	Pow(x, n)	Medium	26.1%	MathBinary Search
35	Search Insert Position	Easy	39.8%	ArrayBinary Search
34	Search for a Range	Medium	31.4%	ArrayBinary Search
33	Search in Rotated Sorted Array	Medium	32.1%	ArrayBinary Search
29	Divide Two Integers	Medium	15.9%	MathBinary Search
91	Decode Ways	Medium	19.9%	StringDynamic Programming
95	Unique Binary Search Trees II	Medium	31.7%	Dynamic ProgrammingTree
17	Letter Combinations of a Phone Number	Medium	35.1%	StringBacktracking
22	Generate Parentheses	Medium	45.9%	StringBacktracking
37	Sudoku Solver	Hard	30.8%	Hash TableBacktracking
39	Combination Sum	Medium	39.5%	ArrayBacktracking
40	Combination Sum II	Medium	34.4%	ArrayBacktracking
44	Wildcard Matching	Hard	20.4%	StringDynamic ProgrammingBacktrackingGreedy
46	Permutations	Medium	44.8%	Backtracking
47	Permutations II	Medium	33.4%	Backtracking
51	N-Queens	Hard	31.7%	Backtracking
52	N-Queens II	Hard	45.5%	Backtracking
60	Permutation Sequence	Medium	28.9%	MathBacktracking
77	Combinations	Medium	40.2%	Backtracking
78	Subsets	Medium	41.8%	ArrayBacktrackingBit Manipulation
79	Word Search	Medium	27.2%	ArrayBacktracking
89	Gray Code	Medium	41.6%	Backtracking
90	Subsets II	Medium	36.9%	ArrayBacktracking
93	Restore IP Addresses	Medium	27.7%	StringBacktracking
294	Flip Game II	Medium	46.5%	Backtracking
126	Word Ladder II	Hard	14.4%	ArrayStringBacktrackingBreadth-first Search
118	Pascal's Triangle	Easy	39.0%	Array
119	Pascal's Triangle II	Easy	37.3%	Array
120	Triangle	Medium	34.1%	ArrayDynamic Programming
121	Best Time to Buy and Sell Stock	Easy	41.7%	ArrayDynamic Programming
122	Best Time to Buy and Sell Stock II	Easy	47.4%	ArrayGreedy
123	Best Time to Buy and Sell Stock III	Hard	29.6%	ArrayDynamic Programming
126	Word Ladder II	Hard	14.4%	ArrayStringBacktrackingBreadth-first Search
117	Populating Next Right Pointers in Each Node II	Medium	33.8%	TreeDepth-first Search
124	Binary Tree Maximum Path Sum	Hard	26.4%	TreeDepth-first Search
125	Valid Palindrome	Easy	26.5%	Two PointersString
117	Populating Next Right Pointers in Each Node II	Medium	33.8%	TreeDepth-first Search
124	Binary Tree Maximum Path Sum	Hard	26.4%	TreeDepth-first Search
123	Best Time to Buy and Sell Stock III	Hard	29.6%	ArrayDynamic Programming
121	Best Time to Buy and Sell Stock	Easy	41.7%	ArrayDynamic Programming
120	Triangle	Medium	34.1%	ArrayDynamic Programming
221	Maximal Square	Medium	29.4%	Dynamic Programming
153	Find Minimum in Rotated Sorted Array	Medium	40.2%	ArrayBinary Search
140	Word Break II	Hard	23.6%	Dynamic ProgrammingBacktracking
128	Longest Consecutive Sequence	Hard	37.3%	ArrayUnion Find
152	Maximum Product Subarray	Medium	26.0%	ArrayDynamic Programming
153	Find Minimum in Rotated Sorted Array	Medium	40.2%	ArrayBinary Search
132	Palindrome Partitioning II	Hard	24.4%	Dynamic Programming
139	Word Break	Medium	30.4%	Dynamic Programming
140	Word Break II	Hard	23.6%	Dynamic ProgrammingBacktracking
152	Maximum Product Subarray	Medium	26.0%	ArrayDynamic Programming
149	Max Points on a Line	Hard	15.3%	Hash TableMath
138	Copy List with Random Pointer	Medium	26.1%	Hash TableLinked List
136	Single Number	Easy	54.8%	Hash TableBit Manipulation
129	Sum Root to Leaf Numbers	Medium	37.0%	TreeDepth-first Search
133	Clone Graph	Medium	25.1%	Depth-first SearchBreadth-first SearchGraph
131	Palindrome Partitioning	Medium	34.0%	Backtracking
141	Linked List Cycle	Easy	35.3%	Linked ListTwo Pointers
142	Linked List Cycle II	Medium	30.9%	Linked ListTwo Pointers
146	LRU Cache	Hard	18.4%	Design
129	Sum Root to Leaf Numbers	Medium	37.0%	TreeDepth-first Search
144	Binary Tree Preorder Traversal	Medium	45.5%	StackTree
145	Binary Tree Postorder Traversal	Hard	40.6%	StackTree
149	Max Points on a Line	Hard	15.3%	Hash TableMath
213	House Robber II	Medium	34.2%	Dynamic Programming
199	Binary Tree Right Side View	Medium	41.5%	TreeDepth-first SearchBreadth-first Search
290	Word Pattern	Easy	33.2%	Hash Table
288	Unique Word Abbreviation	Medium	17.0%	Hash TableDesign
274	H-Index	Medium	33.4%	Hash TableSort
266	Palindrome Permutation	Easy	57.3%	Hash Table
249	Group Shifted Strings	Medium	42.2%	Hash TableString
246	Strobogrammatic Number	Easy	40.0%	Hash TableMath
244	Shortest Word Distance II	Medium	38.9%	Hash TableDesign
200	Number of Islands	Medium	35.2%	Depth-first SearchBreadth-first SearchUnion Find
207	Course Schedule	Medium	32.6%	Depth-first SearchBreadth-first SearchGraphTopological Sort
210	Course Schedule II	Medium	28.7%	Depth-first SearchBreadth-first SearchGraphTopological Sort
257	Binary Tree Paths	Easy	39.3%	TreeDepth-first Search
261	Graph Valid Tree	Medium	38.0%	Depth-first SearchBreadth-first SearchUnion FindGraph
154	Find Minimum in Rotated Sorted Array II	Hard	37.4%	ArrayBinary Search
245	Shortest Word Distance III	Medium	50.6%	Array
243	Shortest Word Distance	Easy	52.8%	Array
238	Product of Array Except Self	Medium	49.6%	Array
229	Majority Element II	Medium	28.7%	Array
228	Summary Ranges	Medium	30.5%	Array
219	Contains Duplicate II	Easy	32.6%	ArrayHash Table
296	Best Meeting Point	Hard	51.9%	MathSort
279	Perfect Squares	Medium	37.3%	MathDynamic ProgrammingBreadth-first Search
273	Integer to English Words	Hard	22.3%	MathString
268	Missing Number	Easy	44.3%	ArrayMathBit Manipulation
264	Ugly Number II	Medium	32.9%	MathDynamic ProgrammingHeap
263	Ugly Number	Easy	39.4%	Math
258	Add Digits	Easy	51.4%	Math
248	Strobogrammatic Number III	Hard	32.1%	MathRecursion
247	Strobogrammatic Number II	Medium	40.3%	MathRecursion
246	Strobogrammatic Number	Easy	40.0%	Hash TableMath
233	Number of Digit One	Hard	28.6%	Math
231	Power of Two	Easy	40.3%	MathBit Manipulation
224	Basic Calculator	Hard	27.5%	MathStack
223	Rectangle Area	Medium	33.2%	Math
204	Count Primes	Easy	26.7%	Hash TableMath
202	Happy Number	Easy	40.9%	Hash TableMath
172	Factorial Trailing Zeroes	Easy	36.3%	Math
171	Excel Sheet Column Number	Easy	47.6%	Math
168	Excel Sheet Column Title	Easy	26.5%	Math
166	Fraction to Recurring Decimal	Medium	17.7%	Hash TableMath
242	Valid Anagram	Easy	46.7%	Hash TableSort
167	Two Sum II - Input array is sorted	Easy	47.1%	ArrayTwo PointersBinary Search
174	Dungeon Game	Hard	23.9%	Binary SearchDynamic Programming
209	Minimum Size Subarray Sum	Medium	31.2%	ArrayTwo PointersBinary Search
222	Count Complete Tree Nodes	Medium	27.6%	Binary SearchTree
230	Kth Smallest Element in a BST	Medium	44.2%	Binary SearchTree
240	Search a 2D Matrix II	Medium	38.7%	Binary SearchDivide and Conquer
270	Closest Binary Search Tree Value	Easy	39.9%	Binary SearchTree
275	H-Index II	Medium	34.6%	Binary Search
278	First Bad Version	Easy	25.6%	Binary Search
287	Find the Duplicate Number	Medium	43.7%	ArrayTwo PointersBinary Search
256	Paint House	Easy	46.2%	Dynamic Programming
264	Ugly Number II	Medium	32.9%	MathDynamic ProgrammingHeap
265	Paint House II	Hard	38.0%	Dynamic Programming
276	Paint Fence	Easy	34.6%	Dynamic Programming
279	Perfect Squares	Medium	37.3%	MathDynamic ProgrammingBreadth-first Search
300	Longest Increasing Subsequence	Medium	38.6%	Binary SearchDynamic Programming
217	Contains Duplicate	Easy	46.1%	ArrayHash Table
216	Combination Sum III	Medium	45.8%	ArrayBacktracking
209	Minimum Size Subarray Sum	Medium	31.2%	ArrayTwo PointersBinary Search
189	Rotate Array	Easy	24.9%	Array
169	Majority Element	Easy	47.0%	ArrayDivide and ConquerBit Manipulation
167	Two Sum II - Input array is sorted	Easy	47.1%	ArrayTwo PointersBinary Search
163	Missing Ranges	Medium	23.9%	Array
162	Find Peak Element	Medium	37.9%	ArrayBinary Search
154	Find Minimum in Rotated Sorted Array II	Hard	37.4%	ArrayBinary Search
198	House Robber	Easy	39.3%	Dynamic Programming
291	Word Pattern II	Hard	38.0%	Backtracking
267	Palindrome Permutation II	Medium	31.9%	Backtracking
254	Factor Combinations	Medium	43.0%	Backtracking
216	Combination Sum III	Medium	45.8%	ArrayBacktracking
212	Word Search II	Hard	23.7%	BacktrackingTrie
211	Add and Search Word - Data structure design	Medium	23.7%	BacktrackingDesignTrie
188	Best Time to Buy and Sell Stock IV	Hard	24.4%	Dynamic Programming
219	Contains Duplicate II	Easy	32.6%	ArrayHash Table
217	Contains Duplicate	Easy	46.1%	ArrayHash Table
205	Isomorphic Strings	Easy	34.1%	Hash Table
204	Count Primes	Easy	26.7%	Hash TableMath
174	Dungeon Game	Hard	23.9%	Binary SearchDynamic Programming
159	Longest Substring with At Most Two Distinct Characters	Hard	41.6%	Hash TableTwo PointersString
166	Fraction to Recurring Decimal	Medium	17.7%	Hash TableMath
297	Serialize and Deserialize Binary Tree	Hard	33.8%	TreeDesign
295	Find Median from Data Stream	Hard	27.5%	HeapDesign
202	Happy Number	Easy	40.9%	Hash TableMath
288	Unique Word Abbreviation	Medium	17.0%	Hash TableDesign
289	Game of Life	Medium	37.1%	Array
287	Find the Duplicate Number	Medium	43.7%	ArrayTwo PointersBinary Search
284	Peeking Iterator	Medium	35.5%	Design
281	Zigzag Iterator	Medium	51.1%	Design
251	Flatten 2D Vector	Medium	40.8%	Design
298	Binary Tree Longest Consecutive Sequence	Medium	41.2%	Tree
297	Serialize and Deserialize Binary Tree	Hard	33.8%	TreeDesign
285	Inorder Successor in BST	Medium	36.2%	Tree
272	Closest Binary Search Tree Value II	Hard	39.3%	StackTree
270	Closest Binary Search Tree Value	Easy	39.9%	Binary SearchTree
257	Binary Tree Paths	Easy	39.3%	TreeDepth-first Search
255	Verify Preorder Sequence in Binary Search Tree	Medium	40.5%	StackTree
250	Count Univalue Subtrees	Medium	42.5%	Tree
236	Lowest Common Ancestor of a Binary Tree	Medium	30.0%	Tree
235	Lowest Common Ancestor of a Binary Search Tree	Easy	39.3%	Tree
230	Kth Smallest Element in a BST	Medium	44.2%	Binary SearchTree
226	Invert Binary Tree	Easy	52.3%	Tree
222	Count Complete Tree Nodes	Medium	27.6%	Binary SearchTree
199	Binary Tree Right Side View	Medium	41.5%	TreeDepth-first SearchBreadth-first Search
173	Binary Search Tree Iterator	Medium	42.0%	StackTreeDesign
156	Binary Tree Upside Down	Medium	44.9%	Tree
244	Shortest Word Distance II	Medium	38.9%	Hash TableDesign
232	Implement Queue using Stacks	Easy	37.2%	StackDesign
225	Implement Stack using Queues	Easy	33.3%	StackDesign
283	Move Zeroes	Easy	50.4%	ArrayTwo Pointers
211	Add and Search Word - Data structure design	Medium	23.7%	BacktrackingDesignTrie
208	Implement Trie (Prefix Tree)	Medium	29.1%	DesignTrie
173	Binary Search Tree Iterator	Medium	42.0%	StackTreeDesign
162	Find Peak Element	Medium	37.9%	ArrayBinary Search
299	Bulls and Cows	Medium	35.2%	Hash Table
159	Longest Substring with At Most Two Distinct Characters	Hard	41.6%	Hash TableTwo PointersString
167	Two Sum II - Input array is sorted	Easy	47.1%	ArrayTwo PointersBinary Search
209	Minimum Size Subarray Sum	Medium	31.2%	ArrayTwo PointersBinary Search
234	Palindrome Linked List	Easy	33.0%	Linked ListTwo Pointers
259	3Sum Smaller	Medium	41.6%	ArrayTwo Pointers
283	Move Zeroes	Easy	50.4%	ArrayTwo Pointers
287	Find the Duplicate Number	Medium	43.7%	ArrayTwo PointersBinary Search
280	Wiggle Sort	Medium	57.6%	ArraySort
277	Find the Celebrity	Medium	35.6%	Array
268	Missing Number	Easy	44.3%	ArrayMathBit Manipulation
259	3Sum Smaller	Medium	41.6%	ArrayTwo Pointers
170	Two Sum III - Data structure design	Easy	25.0%	Hash TableDesign
187	Repeated DNA Sequences	Medium	32.0%	Hash TableBit Manipulation
170	Two Sum III - Data structure design	Easy	25.0%	Hash TableDesign
155	Min Stack	Easy	29.3%	StackDesign
494	Target Sum	Medium	43.4%	Dynamic ProgrammingDepth-first Search
336	Palindrome Pairs	Hard	26.4%	Hash TableStringTrie
320	Generalized Abbreviation	Medium	45.2%	BacktrackingBit Manipulation
325	Maximum Size Subarray Sum Equals k	Medium	42.8%	Hash Table
314	Binary Tree Vertical Order Traversal	Medium	37.1%	Hash Table
311	Sparse Matrix Multiplication	Medium	51.3%	Hash Table
301	Remove Invalid Parentheses	Hard	35.3%	Depth-first SearchBreadth-first Search
323	Number of Connected Components in an Undirected Graph	Medium	48.2%	Depth-first SearchBreadth-first SearchUnion FindGraph
329	Longest Increasing Path in a Matrix	Hard	36.7%	Depth-first SearchTopological SortMemoization
332	Reconstruct Itinerary	Medium	29.4%	Depth-first SearchGraph
335	Self Crossing	Hard	25.6%	Math
326	Power of Three	Easy	40.4%	Math
319	Bulb Switcher	Medium	42.6%	MathBrainteaser
313	Super Ugly Number	Medium	37.9%	MathHeap
303	Range Sum Query - Immutable	Easy	30.4%	Dynamic Programming
304	Range Sum Query 2D - Immutable	Medium	25.8%	Dynamic Programming
309	Best Time to Buy and Sell Stock with Cooldown	Medium	41.1%	Dynamic Programming
312	Burst Balloons	Hard	43.0%	Divide and ConquerDynamic Programming
321	Create Maximum Number	Hard	24.6%	Dynamic ProgrammingGreedy
322	Coin Change	Medium	26.7%	Dynamic Programming
333	Largest BST Subtree	Medium	30.5%	Tree
302	Smallest Rectangle Enclosing Black Pixels	Hard	45.7%	Binary Search
505	The Maze II	Medium	37.7%	Depth-first SearchBreadth-first Search
392	Is Subsequence	Medium	44.6%	Binary SearchDynamic ProgrammingGreedy
350	Intersection of Two Arrays II	Easy	44.7%	Hash TableTwo PointersBinary SearchSort
355	Design Twitter	Medium	25.6%	Hash TableHeapDesign
356	Line Reflection	Medium	30.1%	Hash TableMath
351	Android Unlock Patterns	Medium	44.1%	Dynamic ProgrammingBacktracking
337	House Robber III	Medium	43.9%	TreeDepth-first Search
366	Find Leaves of Binary Tree	Medium	60.1%	TreeDepth-first Search
370	Range Addition	Medium	56.2%	Array
358	Rearrange String k Distance Apart	Hard	31.6%	Hash TableHeapGreedy
359	Logger Rate Limiter	Easy	59.9%	Hash TableDesign
341	Flatten Nested List Iterator	Medium	42.1%	StackDesign
346	Moving Average from Data Stream	Easy	59.1%	DesignQueue
348	Design Tic-Tac-Toe	Medium	45.9%	Design
353	Design Snake Game	Medium	26.7%	DesignQueue
380	Insert Delete GetRandom O(1)	Medium	39.3%	ArrayHash TableDesign
381	Insert Delete GetRandom O(1) - Duplicates allowed	Hard	29.0%	ArrayHash TableDesign
389	Find the Difference	Easy	50.9%	Hash TableBit Manipulation
377	Combination Sum IV	Medium	42.2%	Dynamic Programming
376	Wiggle Subsequence	Medium	35.9%	Dynamic ProgrammingGreedy
375	Guess Number Higher or Lower II	Medium	35.8%	Dynamic ProgrammingMinimax
368	Largest Divisible Subset	Medium	33.8%	MathDynamic Programming
363	Max Sum of Rectangle No Larger Than K	Hard	33.3%	Binary SearchDynamic ProgrammingQueue
361	Bomb Enemy	Medium	39.1%	Dynamic Programming
357	Count Numbers with Unique Digits	Medium	46.1%	MathDynamic ProgrammingBacktracking
354	Russian Doll Envelopes	Hard	32.4%	Binary SearchDynamic Programming
381	Insert Delete GetRandom O(1) - Duplicates allowed	Hard	29.0%	ArrayHash TableDesign
351	Android Unlock Patterns	Medium	44.1%	Dynamic ProgrammingBacktracking
343	Integer Break	Medium	46.2%	MathDynamic Programming
338	Counting Bits	Medium	61.6%	Dynamic ProgrammingBit Manipulation
349	Intersection of Two Arrays	Easy	47.5%	Hash TableTwo PointersBinary SearchSort
350	Intersection of Two Arrays II	Easy	44.7%	Hash TableTwo PointersBinary SearchSort
354	Russian Doll Envelopes	Hard	32.4%	Binary SearchDynamic Programming
363	Max Sum of Rectangle No Larger Than K	Hard	33.3%	Binary SearchDynamic ProgrammingQueue
367	Valid Perfect Square	Easy	38.4%	MathBinary Search
349	Intersection of Two Arrays	Easy	47.5%	Hash TableTwo PointersBinary SearchSort
374	Guess Number Higher or Lower	Easy	35.7%	Binary Search
378	Kth Smallest Element in a Sorted Matrix	Medium	45.0%	Binary SearchHeap
392	Is Subsequence	Medium	44.6%	Binary SearchDynamic ProgrammingGreedy
344	Reverse String	Easy	59.5%	Two PointersString
343	Integer Break	Medium	46.2%	MathDynamic Programming
356	Line Reflection	Medium	30.1%	Hash TableMath
380	Insert Delete GetRandom O(1)	Medium	39.3%	ArrayHash TableDesign
379	Design Phone Directory	Medium	33.6%	Linked ListDesign
362	Design Hit Counter	Medium	54.3%	Design
366	Find Leaves of Binary Tree	Medium	60.1%	TreeDepth-first Search
364	Nested List Weight Sum II	Medium	52.9%	Depth-first Search
339	Nested List Weight Sum	Easy	62.4%	Depth-first Search
357	Count Numbers with Unique Digits	Medium	46.1%	MathDynamic ProgrammingBacktracking
345	Reverse Vowels of a String	Easy	38.6%	Two PointersString
349	Intersection of Two Arrays	Easy	47.5%	Hash TableTwo PointersBinary SearchSort
350	Intersection of Two Arrays II	Easy	44.7%	Hash TableTwo PointersBinary SearchSort
360	Sort Transformed Array	Medium	44.2%	MathTwo Pointers
360	Sort Transformed Array	Medium	44.2%	MathTwo Pointers
365	Water and Jug Problem	Medium	27.7%	Math
367	Valid Perfect Square	Easy	38.4%	MathBinary Search
368	Largest Divisible Subset	Medium	33.8%	MathDynamic Programming
372	Super Pow	Medium	34.5%	Math
380	Insert Delete GetRandom O(1)	Medium	39.3%	ArrayHash TableDesign
337	House Robber III	Medium	43.9%	TreeDepth-first Search
359	Logger Rate Limiter	Easy	59.9%	Hash TableDesign
347	Top K Frequent Elements	Medium	48.5%	Hash TableHeap
381	Insert Delete GetRandom O(1) - Duplicates allowed	Hard	29.0%	ArrayHash TableDesign
355	Design Twitter	Medium	25.6%	Hash TableHeapDesign
357	Count Numbers with Unique Digits	Medium	46.1%	MathDynamic ProgrammingBacktracking
340	Longest Substring with At Most K Distinct Characters	Hard	39.0%	Hash TableString
554	Brick Wall	Medium	45.7%	Hash Table
417	Pacific Atlantic Water Flow	Medium	33.8%	Depth-first SearchBreadth-first Search
411	Minimum Unique Word Abbreviation	Hard	33.0%	BacktrackingBit Manipulation
414	Third Maximum Number	Easy	27.9%	Array
394	Decode String	Medium	41.5%	StackDepth-first Search
415	Add Strings	Easy	41.5%	Math
413	Arithmetic Slices	Medium	54.6%	MathDynamic Programming
400	Nth Digit	Easy	30.0%	Math
416	Partition Equal Subset Sum	Medium	39.3%	Dynamic Programming
413	Arithmetic Slices	Medium	54.6%	MathDynamic Programming
410	Split Array Largest Sum	Hard	38.2%	Binary SearchDynamic Programming
403	Frog Jump	Hard	32.4%	Dynamic Programming
397	Integer Replacement	Medium	30.3%	MathBit Manipulation
396	Rotate Function	Medium	33.3%	Math
409	Longest Palindrome	Easy	45.4%	Hash Table
410	Split Array Largest Sum	Hard	38.2%	Binary SearchDynamic Programming
401	Binary Watch	Easy	44.8%	BacktrackingBit Manipulation
404	Sum of Left Leaves	Easy	47.2%	Tree
594	Longest Harmonious Subsequence	Easy	41.1%	Hash Table
437	Path Sum III	Easy	39.9%	Tree
432	All O`one Data Structure	Hard	28.2%	Design
436	Find Right Interval	Medium	41.4%	Binary Search
423	Reconstruct Original Digits from English	Medium	44.5%	Math
425	Word Squares	Hard	43.1%	BacktrackingTrie
418	Sentence Screen Fitting	Medium	27.8%	Dynamic Programming
593	Valid Square	Medium	40.0%	Math
442	Find All Duplicates in an Array	Medium	56.1%	Array
441	Arranging Coins	Easy	36.3%	MathBinary Search
439	Ternary Expression Parser	Medium	51.1%	StackDepth-first Search
441	Arranging Coins	Easy	36.3%	MathBinary Search
438	Find All Anagrams in a String	Easy	33.7%	Hash Table
582	Kill Process	Medium	49.5%	TreeQueue
447	Number of Boomerangs	Easy	45.4%	Hash Table
446	Arithmetic Slices II - Subsequence	Hard	27.2%	Dynamic Programming
567	Permutation in String	Medium	36.6%	Two Pointers
566	Reshape the Matrix	Easy	58.5%	Array
454	4Sum II	Medium	47.2%	Hash TableBinary Search
454	4Sum II	Medium	47.2%	Hash TableBinary Search
462	Minimum Moves to Equal Array Elements II	Medium	51.8%	Math
460	LFU Cache	Hard	24.3%	Design
463	Island Perimeter	Easy	57.3%	Hash Table
469	Convex Polygon	Medium	32.9%	Math
472	Concatenated Words	Hard	30.3%	Dynamic ProgrammingDepth-first SearchTrie
472	Concatenated Words	Hard	30.3%	Dynamic ProgrammingDepth-first SearchTrie
471	Encode String with Shortest Length	Hard	42.5%	Dynamic Programming
464	Can I Win	Medium	25.0%	Dynamic ProgrammingMinimax
466	Count The Repetitions	Hard	28.0%	Dynamic Programming
467	Unique Substrings in Wraparound String	Medium	32.9%	Dynamic Programming
561	Array Partition I	Easy	66.8%	Array
483	Smallest Good Base	Hard	33.3%	MathBinary Search
474	Ones and Zeroes	Medium	38.9%	Dynamic Programming
483	Smallest Good Base	Hard	33.3%	MathBinary Search
475	Heaters	Easy	29.6%	Binary Search
535	Encode and Decode TinyURL	Medium	74.2%	Hash TableMath
486	Predict the Winner	Medium	45.1%	Dynamic ProgrammingMinimax
485	Max Consecutive Ones	Easy	53.9%	Array
514	Freedom Trail	Hard	39.2%	Divide and ConquerDynamic ProgrammingDepth-first Search
487	Max Consecutive Ones II	Medium	45.5%	Two Pointers
515	Find Largest Value in Each Tree Row	Medium	55.0%	TreeDepth-first SearchBreadth-first Search
453	Minimum Moves to Equal Array Elements	Easy	47.5%	Math
491	Increasing Subsequences	Medium	38.8%	Depth-first Search
494	Target Sum	Medium	43.4%	Dynamic ProgrammingDepth-first Search
490	The Maze	Medium	43.2%	Depth-first SearchBreadth-first Search
488	Zuma Game	Hard	37.5%	Depth-first Search
514	Freedom Trail	Hard	39.2%	Divide and ConquerDynamic ProgrammingDepth-first Search
499	The Maze III	Hard	32.7%	Depth-first SearchBreadth-first Search
495	Teemo Attacking	Medium	51.5%	Array
562	Longest Line of Consecutive One in Matrix	Medium	40.6%	Array
508	Most Frequent Subtree Sum	Medium	52.3%	Hash TableTree
500	Keyboard Row	Easy	59.7%	Hash Table
473	Matchsticks to Square	Medium	35.5%	Depth-first Search
507	Perfect Number	Easy	33.8%	Math
501	Find Mode in Binary Search Tree	Easy	37.7%	Tree
508	Most Frequent Subtree Sum	Medium	52.3%	Hash TableTree
450	Delete Node in a BST	Medium	37.1%	Tree
513	Find Bottom Left Tree Value	Medium	56.1%	TreeDepth-first SearchBreadth-first Search
513	Find Bottom Left Tree Value	Medium	56.1%	TreeDepth-first SearchBreadth-first Search
448	Find All Numbers Disappeared in an Array	Easy	51.2%	Array
563	Binary Tree Tilt	Easy	47.1%	Tree
524	Longest Word in Dictionary through Deleting	Medium	42.9%	Two PointersSort
532	K-diff Pairs in an Array	Easy	28.2%	ArrayTwo Pointers
523	Continuous Subarray Sum	Medium	23.0%	MathDynamic Programming
529	Minesweeper	Medium	49.5%	Depth-first SearchBreadth-first Search
531	Lonely Pixel I	Medium	55.3%	ArrayDepth-first Search
535	Encode and Decode TinyURL	Medium	74.2%	Hash TableMath
517	Super Washing Machines	Hard	36.5%	MathDynamic Programming
533	Lonely Pixel II	Medium	44.2%	ArrayDepth-first Search
533	Lonely Pixel II	Medium	44.2%	ArrayDepth-first Search
523	Continuous Subarray Sum	Medium	23.0%	MathDynamic Programming
517	Super Washing Machines	Hard	36.5%	MathDynamic Programming
516	Longest Palindromic Subsequence	Medium	42.7%	Dynamic Programming
526	Beautiful Arrangement	Medium	54.5%	Backtracking
525	Contiguous Array	Medium	40.5%	Hash Table
531	Lonely Pixel I	Medium	55.3%	ArrayDepth-first Search
532	K-diff Pairs in an Array	Easy	28.2%	ArrayTwo Pointers
560	Subarray Sum Equals K	Medium	40.2%	ArrayMap
545	Boundary of Binary Tree	Medium	31.7%	Tree
543	Diameter of Binary Tree	Easy	44.4%	Tree
538	Convert BST to Greater Tree	Easy	49.4%	Tree
537	Complex Number Multiplication	Medium	64.0%	MathString
542	01 Matrix	Medium	33.3%	Depth-first SearchBreadth-first Search
536	Construct Binary Tree from String	Medium	42.6%	StringTree
515	Find Largest Value in Each Tree Row	Medium	55.0%	TreeDepth-first SearchBreadth-first Search
451	Sort Characters By Frequency	Medium	51.1%	Hash TableHeap
549	Binary Tree Longest Consecutive Sequence II	Medium	41.3%	Tree
547	Friend Circles	Medium	49.2%	Depth-first SearchUnion Find
552	Student Attendance Record II	Hard	31.4%	Dynamic Programming
548	Split Array with Equal Sum	Medium	36.8%	Array
546	Remove Boxes	Hard	34.0%	Dynamic ProgrammingDepth-first Search
553	Optimal Division	Medium	55.1%	MathString
546	Remove Boxes	Hard	34.0%	Dynamic ProgrammingDepth-first Search
449	Serialize and Deserialize BST	Medium	42.5%	Tree
663	Equal Tree Partition	Medium	36.6%	Tree
644	Maximum Average Subarray II	Hard	22.1%	ArrayBinary Search
588	Design In-Memory File System	Hard	34.7%	Design
643	Maximum Average Subarray I	Easy	37.7%	Array
624	Maximum Distance in Arrays	Easy	34.1%	ArrayHash Table
592	Fraction Addition and Subtraction	Medium	46.4%	Math
573	Squirrel Simulation	Medium	52.3%	Math
606	Construct String from Binary Tree	Easy	49.8%	StringTree
632	Smallest Range	Hard	42.4%	Hash TableTwo PointersString
581	Shortest Unsorted Continuous Subarray	Easy	29.5%	Array
575	Distribute Candies	Easy	58.7%	Hash Table
576	Out of Boundary Paths	Medium	30.9%	Dynamic ProgrammingDepth-first Search
568	Maximum Vacation Days	Hard	39.9%	Dynamic Programming
576	Out of Boundary Paths	Medium	30.9%	Dynamic ProgrammingDepth-first Search
628	Maximum Product of Three Numbers	Easy	45.0%	ArrayMath
639	Decode Ways II	Hard	23.6%	Dynamic Programming
572	Subtree of Another Tree	Easy	40.8%	Tree
644	Maximum Average Subarray II	Hard	22.1%	ArrayBinary Search
638	Shopping Offers	Medium	42.9%	Dynamic ProgrammingDepth-first Search
621	Task Scheduler	Medium	42.1%	ArrayGreedyQueue
642	Design Search Autocomplete System	Hard	30.0%	DesignTrie
598	Range Addition II	Easy	48.2%	Math
600	Non-negative Integers without Consecutive Ones	Hard	30.4%	Dynamic Programming
637	Average of Levels in Binary Tree	Easy	55.8%	Tree
635	Design Log Storage System	Medium	48.4%	StringDesign
599	Minimum Index Sum of Two Lists	Easy	46.3%	Hash Table
631	Design Excel Sum Formula	Hard	26.6%	Design
629	K Inverse Pairs Array	Hard	26.7%	Dynamic Programming
604	Design Compressed String Iterator	Easy	32.4%	Design
609	Find Duplicate File in System	Medium	52.5%	Hash TableString
605	Can Place Flowers	Easy	30.0%	Array
611	Valid Triangle Number	Medium	41.7%	Array
617	Merge Two Binary Trees	Easy	67.9%	Tree
634	Find the Derangement of An Array	Medium	33.8%	Math
633	Sum of Square Numbers	Easy	32.2%	Math
628	Maximum Product of Three Numbers	Easy	45.0%	ArrayMath
625	Minimum Factorization	Medium	30.7%	MathRecursion
624	Maximum Distance in Arrays	Easy	34.1%	ArrayHash Table
632	Smallest Range	Hard	42.4%	Hash TableTwo PointersString
623	Add One Row to Tree	Medium	46.6%	Tree
640	Solve the Equation	Medium	39.0%	Math
638	Shopping Offers	Medium	42.9%	Dynamic ProgrammingDepth-first Search
667	Beautiful Arrangement II	Medium	51.6%	Array
671	Second Minimum Node In a Binary Tree	Easy	41.9%	Tree
670	Maximum Swap	Medium	38.4%	ArrayMath
646	Maximum Length of Pair Chain	Medium	47.7%	Dynamic Programming
661	Image Smoother	Easy	45.8%	Array
645	Set Mismatch	Easy	40.3%	Hash TableMath
658	Find K Closest Elements	Medium	35.7%	Binary Search
660	Remove 9	Hard	47.1%	Math
651	4 Keys Keyboard	Medium	47.9%	MathDynamic ProgrammingGreedy
652	Find Duplicate Subtrees	Medium	34.9%	Tree
653	Two Sum IV - Input is a BST	Easy	50.7%	Tree
654	Maximum Binary Tree	Medium	70.2%	Tree
655	Print Binary Tree	Medium	50.6%	Tree
656	Coin Path	Hard	24.5%	Dynamic Programming
647	Palindromic Substrings	Medium	55.8%	StringDynamic Programming
651	4 Keys Keyboard	Medium	47.9%	MathDynamic ProgrammingGreedy
650	2 Keys Keyboard	Medium	44.1%	Dynamic Programming
662	Maximum Width of Binary Tree	Medium	37.7%	Tree
648	Replace Words	Medium	47.7%	Hash TableTrie
670	Maximum Swap	Medium	38.4%	ArrayMath
664	Strange Printer	Hard	31.4%	Dynamic ProgrammingDepth-first Search
664	Strange Printer	Hard	31.4%	Dynamic ProgrammingDepth-first Search
669	Trim a Binary Search Tree	Easy	58.4%	Tree
666	Path Sum IV	Medium	49.4%	Tree
665	Non-decreasing Array	Easy	21.3%	Array
668	Kth Smallest Number in Multiplication Table	Hard	37.0%	Binary Search
645	Set Mismatch	Easy	40.3%	Hash TableMath
694	Number of Distinct Islands	Medium	43.5%	Hash TableDepth-first Search
676	Implement Magic Dictionary	Medium	50.0%	Hash TableTrie
674	Longest Continuous Increasing Subsequence	Easy	43.0%	Array
672	Bulb Switcher II	Medium	48.1%	Math
673	Number of Longest Increasing Subsequence	Medium	30.9%	Dynamic Programming
690	Employee Importance	Easy	55.5%	Hash TableDepth-first SearchBreadth-first Search
684	Redundant Connection	Medium	35.8%	TreeUnion FindGraph
683	K Empty Slots	Hard	37.2%	ArrayBinary Search Tree
679	24 Game	Hard	38.5%	Depth-first Search
689	Maximum Sum of 3 Non-Overlapping Subarrays	Hard	42.9%	ArrayDynamic Programming
685	Redundant Connection II	Hard	28.8%	TreeDepth-first SearchUnion FindGraph
685	Redundant Connection II	Hard	28.8%	TreeDepth-first SearchUnion FindGraph
692	Top K Frequent Words	Medium	41.1%	Hash TableHeapTrie
687	Longest Univalue Path	Easy	32.3%	TreeRecursion
695	Max Area of Island	Easy	53.3%	ArrayDepth-first Search
691	Stickers to Spell Word	Hard	31.7%	Dynamic ProgrammingBacktracking
689	Maximum Sum of 3 Non-Overlapping Subarrays	Hard	42.9%	ArrayDynamic Programming
690	Employee Importance	Easy	55.5%	Hash TableDepth-first SearchBreadth-first Search
688	Knight Probability in Chessboard	Medium	38.3%	Dynamic Programming
691	Stickers to Spell Word	Hard	31.7%	Dynamic ProgrammingBacktracking
694	Number of Distinct Islands	Medium	43.5%	Hash TableDepth-first Search
695	Max Area of Island	Easy	53.3%	ArrayDepth-first Search
697	Degree of an Array	Easy	48.9%	Array
698	Partition to K Equal Sum Subsets	Medium	34.7%	Dynamic ProgrammingRecursion
711	Number of Distinct Islands II	Hard	26.0%	Hash TableDepth-first Search
711	Number of Distinct Islands II	Hard	26.0%	Hash TableDepth-first Search

Tag:math

ID	Title	Difficulty	Acceptance	Tags
208	Implement Trie (Prefix Tree)	Medium	29.1%	DesignTrie
116	Populating Next Right Pointers in Each Node	Medium	36.9%	TreeDepth-first Search
1	Two Sum	Easy	35.6%	ArrayHash Table
4	Median of Two Sorted Arrays	Hard	22.1%	ArrayBinary SearchDivide and Conquer
3	Longest Substring Without Repeating Characters	Medium	24.4%	Hash TableTwo PointersString
2	Add Two Numbers	Medium	28.0%	Linked ListMath
7	Reverse Integer	Easy	24.5%	Math
8	String to Integer (atoi)	Medium	14.0%	MathString
9	Palindrome Number	Easy	35.5%	Math
10	Regular Expression Matching	Hard	24.2%	StringDynamic ProgrammingBacktracking
4	Median of Two Sorted Arrays	Hard	22.1%	ArrayBinary SearchDivide and Conquer
1	Two Sum	Easy	35.6%	ArrayHash Table
3	Longest Substring Without Repeating Characters	Medium	24.4%	Hash TableTwo PointersString
107	Binary Tree Level Order Traversal II	Easy	40.8%	TreeBreadth-first Search
42	Trapping Rain Water	Hard	37.0%	ArrayTwo PointersStack
45	Jump Game II	Hard	26.2%	ArrayGreedy
48	Rotate Image	Medium	39.5%	Array
53	Maximum Subarray	Easy	39.8%	ArrayDivide and ConquerDynamic Programming
54	Spiral Matrix	Medium	26.4%	Array
55	Jump Game	Medium	29.5%	ArrayGreedy
56	Merge Intervals	Medium	30.7%	ArraySort
57	Insert Interval	Hard	28.1%	ArraySort
59	Spiral Matrix II	Medium	40.1%	Array
62	Unique Paths	Medium	41.7%	ArrayDynamic Programming
63	Unique Paths II	Medium	31.9%	ArrayDynamic Programming
64	Minimum Path Sum	Medium	38.9%	ArrayDynamic Programming
66	Plus One	Easy	38.9%	ArrayMath
73	Set Matrix Zeroes	Medium	36.1%	Array
74	Search a 2D Matrix	Medium	34.9%	ArrayBinary Search
75	Sort Colors	Medium	38.3%	ArrayTwo PointersSort
78	Subsets	Medium	41.8%	ArrayBacktrackingBit Manipulation
79	Word Search	Medium	27.2%	ArrayBacktracking
80	Remove Duplicates from Sorted Array II	Medium	36.3%	ArrayTwo Pointers
81	Search in Rotated Sorted Array II	Medium	32.7%	ArrayBinary Search
84	Largest Rectangle in Histogram	Hard	27.0%	ArrayStack
85	Maximal Rectangle	Hard	28.5%	ArrayHash TableDynamic ProgrammingStack
88	Merge Sorted Array	Easy	32.1%	ArrayTwo Pointers
90	Subsets II	Medium	36.9%	ArrayBacktracking
105	Construct Binary Tree from Preorder and Inorder Traversal	Medium	32.6%	ArrayTreeDepth-first Search
106	Construct Binary Tree from Inorder and Postorder Traversal	Medium	32.4%	ArrayTreeDepth-first Search
41	First Missing Positive	Hard	25.6%	Array
40	Combination Sum II	Medium	34.4%	ArrayBacktracking
39	Combination Sum	Medium	39.5%	ArrayBacktracking
35	Search Insert Position	Easy	39.8%	ArrayBinary Search
34	Search for a Range	Medium	31.4%	ArrayBinary Search
33	Search in Rotated Sorted Array	Medium	32.1%	ArrayBinary Search
31	Next Permutation	Medium	28.8%	Array
27	Remove Element	Easy	39.6%	ArrayTwo Pointers
26	Remove Duplicates from Sorted Array	Easy	35.4%	ArrayTwo Pointers
18	4Sum	Medium	27.0%	ArrayHash TableTwo Pointers
16	3Sum Closest	Medium	31.3%	ArrayTwo Pointers
15	3Sum	Medium	21.8%	ArrayTwo Pointers
11	Container With Most Water	Medium	36.8%	ArrayTwo Pointers
98	Validate Binary Search Tree	Medium	23.6%	TreeDepth-first Search
99	Recover Binary Search Tree	Hard	30.2%	TreeDepth-first Search
100	Same Tree	Easy	46.8%	TreeDepth-first Search
101	Symmetric Tree	Easy	39.2%	TreeDepth-first SearchBreadth-first Search
104	Maximum Depth of Binary Tree	Easy	53.1%	TreeDepth-first Search
105	Construct Binary Tree from Preorder and Inorder Traversal	Medium	32.6%	ArrayTreeDepth-first Search
106	Construct Binary Tree from Inorder and Postorder Traversal	Medium	32.4%	ArrayTreeDepth-first Search
94	Binary Tree Inorder Traversal	Medium	47.4%	Hash TableStackTree
85	Maximal Rectangle	Hard	28.5%	ArrayHash TableDynamic ProgrammingStack
76	Minimum Window Substring	Hard	25.9%	Hash TableTwo PointersString
49	Group Anagrams	Medium	35.9%	Hash TableString
37	Sudoku Solver	Hard	30.8%	Hash TableBacktracking
36	Valid Sudoku	Medium	36.3%	Hash Table
30	Substring with Concatenation of All Words	Hard	22.0%	Hash TableTwo PointersString
18	4Sum	Medium	27.0%	ArrayHash TableTwo Pointers
32	Longest Valid Parentheses	Hard	23.1%	StringDynamic Programming
44	Wildcard Matching	Hard	20.4%	StringDynamic ProgrammingBacktrackingGreedy
53	Maximum Subarray	Easy	39.8%	ArrayDivide and ConquerDynamic Programming
62	Unique Paths	Medium	41.7%	ArrayDynamic Programming
63	Unique Paths II	Medium	31.9%	ArrayDynamic Programming
64	Minimum Path Sum	Medium	38.9%	ArrayDynamic Programming
70	Climbing Stairs	Easy	40.3%	Dynamic Programming
108	Convert Sorted Array to Binary Search Tree	Easy	42.5%	TreeDepth-first Search
109	Convert Sorted List to Binary Search Tree	Medium	34.4%	Linked ListDepth-first Search
110	Balanced Binary Tree	Easy	37.8%	TreeDepth-first Search
111	Minimum Depth of Binary Tree	Easy	33.3%	TreeDepth-first SearchBreadth-first Search
112	Path Sum	Easy	34.2%	TreeDepth-first Search
113	Path Sum II	Medium	34.3%	TreeDepth-first Search
114	Flatten Binary Tree to Linked List	Medium	35.5%	TreeDepth-first Search
116	Populating Next Right Pointers in Each Node	Medium	36.9%	TreeDepth-first Search
11	Container With Most Water	Medium	36.8%	ArrayTwo Pointers
15	3Sum	Medium	21.8%	ArrayTwo Pointers
16	3Sum Closest	Medium	31.3%	ArrayTwo Pointers
18	4Sum	Medium	27.0%	ArrayHash TableTwo Pointers
19	Remove Nth Node From End of List	Medium	33.8%	Linked ListTwo Pointers
26	Remove Duplicates from Sorted Array	Easy	35.4%	ArrayTwo Pointers
27	Remove Element	Easy	39.6%	ArrayTwo Pointers
28	Implement strStr()	Easy	28.4%	Two PointersString
30	Substring with Concatenation of All Words	Hard	22.0%	Hash TableTwo PointersString
42	Trapping Rain Water	Hard	37.0%	ArrayTwo PointersStack
61	Rotate List	Medium	24.3%	Linked ListTwo Pointers
75	Sort Colors	Medium	38.3%	ArrayTwo PointersSort
76	Minimum Window Substring	Hard	25.9%	Hash TableTwo PointersString
80	Remove Duplicates from Sorted Array II	Medium	36.3%	ArrayTwo Pointers
86	Partition List	Medium	33.0%	Linked ListTwo Pointers
88	Merge Sorted Array	Easy	32.1%	ArrayTwo Pointers
94	Binary Tree Inorder Traversal	Medium	47.4%	Hash TableStackTree
95	Unique Binary Search Trees II	Medium	31.7%	Dynamic ProgrammingTree
96	Unique Binary Search Trees	Medium	41.3%	Dynamic ProgrammingTree
72	Edit Distance	Hard	32.0%	StringDynamic Programming
85	Maximal Rectangle	Hard	28.5%	ArrayHash TableDynamic ProgrammingStack
87	Scramble String	Hard	29.4%	StringDynamic Programming
98	Validate Binary Search Tree	Medium	23.6%	TreeDepth-first Search
99	Recover Binary Search Tree	Hard	30.2%	TreeDepth-first Search
100	Same Tree	Easy	46.8%	TreeDepth-first Search
101	Symmetric Tree	Easy	39.2%	TreeDepth-first SearchBreadth-first Search
102	Binary Tree Level Order Traversal	Medium	40.6%	TreeBreadth-first Search
103	Binary Tree Zigzag Level Order Traversal	Medium	35.2%	StackTreeBreadth-first Search
104	Maximum Depth of Binary Tree	Easy	53.1%	TreeDepth-first Search
105	Construct Binary Tree from Preorder and Inorder Traversal	Medium	32.6%	ArrayTreeDepth-first Search
106	Construct Binary Tree from Inorder and Postorder Traversal	Medium	32.4%	ArrayTreeDepth-first Search
108	Convert Sorted Array to Binary Search Tree	Easy	42.5%	TreeDepth-first Search
110	Balanced Binary Tree	Easy	37.8%	TreeDepth-first Search
111	Minimum Depth of Binary Tree	Easy	33.3%	TreeDepth-first SearchBreadth-first Search
112	Path Sum	Easy	34.2%	TreeDepth-first Search
113	Path Sum II	Medium	34.3%	TreeDepth-first Search
114	Flatten Binary Tree to Linked List	Medium	35.5%	TreeDepth-first Search
10	Regular Expression Matching	Hard	24.2%	StringDynamic ProgrammingBacktracking
12	Integer to Roman	Medium	45.3%	MathString
13	Roman to Integer	Easy	46.4%	MathString
29	Divide Two Integers	Medium	15.9%	MathBinary Search
43	Multiply Strings	Medium	27.5%	MathString
50	Pow(x, n)	Medium	26.1%	MathBinary Search
60	Permutation Sequence	Medium	28.9%	MathBacktracking
65	Valid Number	Hard	12.8%	MathString
66	Plus One	Easy	38.9%	ArrayMath
67	Add Binary	Easy	33.0%	MathString
69	Sqrt(x)	Easy	28.0%	MathBinary Search
115	Distinct Subsequences	Hard	31.7%	StringDynamic Programming
97	Interleaving String	Hard	24.8%	StringDynamic Programming
96	Unique Binary Search Trees	Medium	41.3%	Dynamic ProgrammingTree
81	Search in Rotated Sorted Array II	Medium	32.7%	ArrayBinary Search
74	Search a 2D Matrix	Medium	34.9%	ArrayBinary Search
69	Sqrt(x)	Easy	28.0%	MathBinary Search
50	Pow(x, n)	Medium	26.1%	MathBinary Search
35	Search Insert Position	Easy	39.8%	ArrayBinary Search
34	Search for a Range	Medium	31.4%	ArrayBinary Search
33	Search in Rotated Sorted Array	Medium	32.1%	ArrayBinary Search
29	Divide Two Integers	Medium	15.9%	MathBinary Search
91	Decode Ways	Medium	19.9%	StringDynamic Programming
95	Unique Binary Search Trees II	Medium	31.7%	Dynamic ProgrammingTree
17	Letter Combinations of a Phone Number	Medium	35.1%	StringBacktracking
22	Generate Parentheses	Medium	45.9%	StringBacktracking
37	Sudoku Solver	Hard	30.8%	Hash TableBacktracking
39	Combination Sum	Medium	39.5%	ArrayBacktracking
40	Combination Sum II	Medium	34.4%	ArrayBacktracking
44	Wildcard Matching	Hard	20.4%	StringDynamic ProgrammingBacktrackingGreedy
46	Permutations	Medium	44.8%	Backtracking
47	Permutations II	Medium	33.4%	Backtracking
51	N-Queens	Hard	31.7%	Backtracking
52	N-Queens II	Hard	45.5%	Backtracking
60	Permutation Sequence	Medium	28.9%	MathBacktracking
77	Combinations	Medium	40.2%	Backtracking
78	Subsets	Medium	41.8%	ArrayBacktrackingBit Manipulation
79	Word Search	Medium	27.2%	ArrayBacktracking
89	Gray Code	Medium	41.6%	Backtracking
90	Subsets II	Medium	36.9%	ArrayBacktracking
93	Restore IP Addresses	Medium	27.7%	StringBacktracking
343	Integer Break	Medium	46.2%	MathDynamic Programming
294	Flip Game II	Medium	46.5%	Backtracking
118	Pascal's Triangle	Easy	39.0%	Array
119	Pascal's Triangle II	Easy	37.3%	Array
120	Triangle	Medium	34.1%	ArrayDynamic Programming
121	Best Time to Buy and Sell Stock	Easy	41.7%	ArrayDynamic Programming
122	Best Time to Buy and Sell Stock II	Easy	47.4%	ArrayGreedy
123	Best Time to Buy and Sell Stock III	Hard	29.6%	ArrayDynamic Programming
126	Word Ladder II	Hard	14.4%	ArrayStringBacktrackingBreadth-first Search
117	Populating Next Right Pointers in Each Node II	Medium	33.8%	TreeDepth-first Search
124	Binary Tree Maximum Path Sum	Hard	26.4%	TreeDepth-first Search
125	Valid Palindrome	Easy	26.5%	Two PointersString
117	Populating Next Right Pointers in Each Node II	Medium	33.8%	TreeDepth-first Search
124	Binary Tree Maximum Path Sum	Hard	26.4%	TreeDepth-first Search
123	Best Time to Buy and Sell Stock III	Hard	29.6%	ArrayDynamic Programming
121	Best Time to Buy and Sell Stock	Easy	41.7%	ArrayDynamic Programming
120	Triangle	Medium	34.1%	ArrayDynamic Programming
221	Maximal Square	Medium	29.4%	Dynamic Programming
153	Find Minimum in Rotated Sorted Array	Medium	40.2%	ArrayBinary Search
140	Word Break II	Hard	23.6%	Dynamic ProgrammingBacktracking
128	Longest Consecutive Sequence	Hard	37.3%	ArrayUnion Find
152	Maximum Product Subarray	Medium	26.0%	ArrayDynamic Programming
153	Find Minimum in Rotated Sorted Array	Medium	40.2%	ArrayBinary Search
132	Palindrome Partitioning II	Hard	24.4%	Dynamic Programming
139	Word Break	Medium	30.4%	Dynamic Programming
140	Word Break II	Hard	23.6%	Dynamic ProgrammingBacktracking
152	Maximum Product Subarray	Medium	26.0%	ArrayDynamic Programming
149	Max Points on a Line	Hard	15.3%	Hash TableMath
138	Copy List with Random Pointer	Medium	26.1%	Hash TableLinked List
136	Single Number	Easy	54.8%	Hash TableBit Manipulation
129	Sum Root to Leaf Numbers	Medium	37.0%	TreeDepth-first Search
133	Clone Graph	Medium	25.1%	Depth-first SearchBreadth-first SearchGraph
131	Palindrome Partitioning	Medium	34.0%	Backtracking
141	Linked List Cycle	Easy	35.3%	Linked ListTwo Pointers
142	Linked List Cycle II	Medium	30.9%	Linked ListTwo Pointers
146	LRU Cache	Hard	18.4%	Design
129	Sum Root to Leaf Numbers	Medium	37.0%	TreeDepth-first Search
144	Binary Tree Preorder Traversal	Medium	45.5%	StackTree
145	Binary Tree Postorder Traversal	Hard	40.6%	StackTree
149	Max Points on a Line	Hard	15.3%	Hash TableMath
213	House Robber II	Medium	34.2%	Dynamic Programming
199	Binary Tree Right Side View	Medium	41.5%	TreeDepth-first SearchBreadth-first Search
290	Word Pattern	Easy	33.2%	Hash Table
288	Unique Word Abbreviation	Medium	17.0%	Hash TableDesign
274	H-Index	Medium	33.4%	Hash TableSort
266	Palindrome Permutation	Easy	57.3%	Hash Table
249	Group Shifted Strings	Medium	42.2%	Hash TableString
246	Strobogrammatic Number	Easy	40.0%	Hash TableMath
244	Shortest Word Distance II	Medium	38.9%	Hash TableDesign
200	Number of Islands	Medium	35.2%	Depth-first SearchBreadth-first SearchUnion Find
207	Course Schedule	Medium	32.6%	Depth-first SearchBreadth-first SearchGraphTopological Sort
210	Course Schedule II	Medium	28.7%	Depth-first SearchBreadth-first SearchGraphTopological Sort
257	Binary Tree Paths	Easy	39.3%	TreeDepth-first Search
261	Graph Valid Tree	Medium	38.0%	Depth-first SearchBreadth-first SearchUnion FindGraph
154	Find Minimum in Rotated Sorted Array II	Hard	37.4%	ArrayBinary Search
245	Shortest Word Distance III	Medium	50.6%	Array
243	Shortest Word Distance	Easy	52.8%	Array
238	Product of Array Except Self	Medium	49.6%	Array
229	Majority Element II	Medium	28.7%	Array
228	Summary Ranges	Medium	30.5%	Array
219	Contains Duplicate II	Easy	32.6%	ArrayHash Table
126	Word Ladder II	Hard	14.4%	ArrayStringBacktrackingBreadth-first Search
279	Perfect Squares	Medium	37.3%	MathDynamic ProgrammingBreadth-first Search
273	Integer to English Words	Hard	22.3%	MathString
268	Missing Number	Easy	44.3%	ArrayMathBit Manipulation
264	Ugly Number II	Medium	32.9%	MathDynamic ProgrammingHeap
263	Ugly Number	Easy	39.4%	Math
258	Add Digits	Easy	51.4%	Math
248	Strobogrammatic Number III	Hard	32.1%	MathRecursion
247	Strobogrammatic Number II	Medium	40.3%	MathRecursion
246	Strobogrammatic Number	Easy	40.0%	Hash TableMath
233	Number of Digit One	Hard	28.6%	Math
231	Power of Two	Easy	40.3%	MathBit Manipulation
224	Basic Calculator	Hard	27.5%	MathStack
223	Rectangle Area	Medium	33.2%	Math
204	Count Primes	Easy	26.7%	Hash TableMath
202	Happy Number	Easy	40.9%	Hash TableMath
172	Factorial Trailing Zeroes	Easy	36.3%	Math
171	Excel Sheet Column Number	Easy	47.6%	Math
168	Excel Sheet Column Title	Easy	26.5%	Math
166	Fraction to Recurring Decimal	Medium	17.7%	Hash TableMath
242	Valid Anagram	Easy	46.7%	Hash TableSort
167	Two Sum II - Input array is sorted	Easy	47.1%	ArrayTwo PointersBinary Search
174	Dungeon Game	Hard	23.9%	Binary SearchDynamic Programming
209	Minimum Size Subarray Sum	Medium	31.2%	ArrayTwo PointersBinary Search
222	Count Complete Tree Nodes	Medium	27.6%	Binary SearchTree
230	Kth Smallest Element in a BST	Medium	44.2%	Binary SearchTree
240	Search a 2D Matrix II	Medium	38.7%	Binary SearchDivide and Conquer
270	Closest Binary Search Tree Value	Easy	39.9%	Binary SearchTree
275	H-Index II	Medium	34.6%	Binary Search
278	First Bad Version	Easy	25.6%	Binary Search
287	Find the Duplicate Number	Medium	43.7%	ArrayTwo PointersBinary Search
256	Paint House	Easy	46.2%	Dynamic Programming
264	Ugly Number II	Medium	32.9%	MathDynamic ProgrammingHeap
265	Paint House II	Hard	38.0%	Dynamic Programming
276	Paint Fence	Easy	34.6%	Dynamic Programming
279	Perfect Squares	Medium	37.3%	MathDynamic ProgrammingBreadth-first Search
155	Min Stack	Easy	29.3%	StackDesign
217	Contains Duplicate	Easy	46.1%	ArrayHash Table
216	Combination Sum III	Medium	45.8%	ArrayBacktracking
209	Minimum Size Subarray Sum	Medium	31.2%	ArrayTwo PointersBinary Search
189	Rotate Array	Easy	24.9%	Array
169	Majority Element	Easy	47.0%	ArrayDivide and ConquerBit Manipulation
167	Two Sum II - Input array is sorted	Easy	47.1%	ArrayTwo PointersBinary Search
163	Missing Ranges	Medium	23.9%	Array
162	Find Peak Element	Medium	37.9%	ArrayBinary Search
154	Find Minimum in Rotated Sorted Array II	Hard	37.4%	ArrayBinary Search
198	House Robber	Easy	39.3%	Dynamic Programming
291	Word Pattern II	Hard	38.0%	Backtracking
267	Palindrome Permutation II	Medium	31.9%	Backtracking
254	Factor Combinations	Medium	43.0%	Backtracking
216	Combination Sum III	Medium	45.8%	ArrayBacktracking
212	Word Search II	Hard	23.7%	BacktrackingTrie
211	Add and Search Word - Data structure design	Medium	23.7%	BacktrackingDesignTrie
188	Best Time to Buy and Sell Stock IV	Hard	24.4%	Dynamic Programming
219	Contains Duplicate II	Easy	32.6%	ArrayHash Table
217	Contains Duplicate	Easy	46.1%	ArrayHash Table
205	Isomorphic Strings	Easy	34.1%	Hash Table
204	Count Primes	Easy	26.7%	Hash TableMath
174	Dungeon Game	Hard	23.9%	Binary SearchDynamic Programming
159	Longest Substring with At Most Two Distinct Characters	Hard	41.6%	Hash TableTwo PointersString
166	Fraction to Recurring Decimal	Medium	17.7%	Hash TableMath
170	Two Sum III - Data structure design	Easy	25.0%	Hash TableDesign
187	Repeated DNA Sequences	Medium	32.0%	Hash TableBit Manipulation
202	Happy Number	Easy	40.9%	Hash TableMath
288	Unique Word Abbreviation	Medium	17.0%	Hash TableDesign
289	Game of Life	Medium	37.1%	Array
287	Find the Duplicate Number	Medium	43.7%	ArrayTwo PointersBinary Search
284	Peeking Iterator	Medium	35.5%	Design
281	Zigzag Iterator	Medium	51.1%	Design
251	Flatten 2D Vector	Medium	40.8%	Design
170	Two Sum III - Data structure design	Easy	25.0%	Hash TableDesign
259	3Sum Smaller	Medium	41.6%	ArrayTwo Pointers
285	Inorder Successor in BST	Medium	36.2%	Tree
272	Closest Binary Search Tree Value II	Hard	39.3%	StackTree
270	Closest Binary Search Tree Value	Easy	39.9%	Binary SearchTree
257	Binary Tree Paths	Easy	39.3%	TreeDepth-first Search
255	Verify Preorder Sequence in Binary Search Tree	Medium	40.5%	StackTree
250	Count Univalue Subtrees	Medium	42.5%	Tree
236	Lowest Common Ancestor of a Binary Tree	Medium	30.0%	Tree
235	Lowest Common Ancestor of a Binary Search Tree	Easy	39.3%	Tree
230	Kth Smallest Element in a BST	Medium	44.2%	Binary SearchTree
226	Invert Binary Tree	Easy	52.3%	Tree
222	Count Complete Tree Nodes	Medium	27.6%	Binary SearchTree
199	Binary Tree Right Side View	Medium	41.5%	TreeDepth-first SearchBreadth-first Search
173	Binary Search Tree Iterator	Medium	42.0%	StackTreeDesign
156	Binary Tree Upside Down	Medium	44.9%	Tree
244	Shortest Word Distance II	Medium	38.9%	Hash TableDesign
232	Implement Queue using Stacks	Easy	37.2%	StackDesign
225	Implement Stack using Queues	Easy	33.3%	StackDesign
283	Move Zeroes	Easy	50.4%	ArrayTwo Pointers
211	Add and Search Word - Data structure design	Medium	23.7%	BacktrackingDesignTrie
268	Missing Number	Easy	44.3%	ArrayMathBit Manipulation
173	Binary Search Tree Iterator	Medium	42.0%	StackTreeDesign
162	Find Peak Element	Medium	37.9%	ArrayBinary Search
277	Find the Celebrity	Medium	35.6%	Array
159	Longest Substring with At Most Two Distinct Characters	Hard	41.6%	Hash TableTwo PointersString
167	Two Sum II - Input array is sorted	Easy	47.1%	ArrayTwo PointersBinary Search
209	Minimum Size Subarray Sum	Medium	31.2%	ArrayTwo PointersBinary Search
234	Palindrome Linked List	Easy	33.0%	Linked ListTwo Pointers
259	3Sum Smaller	Medium	41.6%	ArrayTwo Pointers
283	Move Zeroes	Easy	50.4%	ArrayTwo Pointers
287	Find the Duplicate Number	Medium	43.7%	ArrayTwo PointersBinary Search
280	Wiggle Sort	Medium	57.6%	ArraySort
514	Freedom Trail	Hard	39.2%	Divide and ConquerDynamic ProgrammingDepth-first Search
299	Bulls and Cows	Medium	35.2%	Hash Table
297	Serialize and Deserialize Binary Tree	Hard	33.8%	TreeDesign
298	Binary Tree Longest Consecutive Sequence	Medium	41.2%	Tree
295	Find Median from Data Stream	Hard	27.5%	HeapDesign
297	Serialize and Deserialize Binary Tree	Hard	33.8%	TreeDesign
296	Best Meeting Point	Hard	51.9%	MathSort
453	Minimum Moves to Equal Array Elements	Easy	47.5%	Math
494	Target Sum	Medium	43.4%	Dynamic ProgrammingDepth-first Search
320	Generalized Abbreviation	Medium	45.2%	BacktrackingBit Manipulation
325	Maximum Size Subarray Sum Equals k	Medium	42.8%	Hash Table
314	Binary Tree Vertical Order Traversal	Medium	37.1%	Hash Table
311	Sparse Matrix Multiplication	Medium	51.3%	Hash Table
301	Remove Invalid Parentheses	Hard	35.3%	Depth-first SearchBreadth-first Search
323	Number of Connected Components in an Undirected Graph	Medium	48.2%	Depth-first SearchBreadth-first SearchUnion FindGraph
329	Longest Increasing Path in a Matrix	Hard	36.7%	Depth-first SearchTopological SortMemoization
332	Reconstruct Itinerary	Medium	29.4%	Depth-first SearchGraph
335	Self Crossing	Hard	25.6%	Math
326	Power of Three	Easy	40.4%	Math
319	Bulb Switcher	Medium	42.6%	MathBrainteaser
313	Super Ugly Number	Medium	37.9%	MathHeap
303	Range Sum Query - Immutable	Easy	30.4%	Dynamic Programming
304	Range Sum Query 2D - Immutable	Medium	25.8%	Dynamic Programming
309	Best Time to Buy and Sell Stock with Cooldown	Medium	41.1%	Dynamic Programming
312	Burst Balloons	Hard	43.0%	Divide and ConquerDynamic Programming
321	Create Maximum Number	Hard	24.6%	Dynamic ProgrammingGreedy
322	Coin Change	Medium	26.7%	Dynamic Programming
333	Largest BST Subtree	Medium	30.5%	Tree
302	Smallest Rectangle Enclosing Black Pixels	Hard	45.7%	Binary Search
449	Serialize and Deserialize BST	Medium	42.5%	Tree
392	Is Subsequence	Medium	44.6%	Binary SearchDynamic ProgrammingGreedy
350	Intersection of Two Arrays II	Easy	44.7%	Hash TableTwo PointersBinary SearchSort
355	Design Twitter	Medium	25.6%	Hash TableHeapDesign
356	Line Reflection	Medium	30.1%	Hash TableMath
351	Android Unlock Patterns	Medium	44.1%	Dynamic ProgrammingBacktracking
337	House Robber III	Medium	43.9%	TreeDepth-first Search
366	Find Leaves of Binary Tree	Medium	60.1%	TreeDepth-first Search
370	Range Addition	Medium	56.2%	Array
358	Rearrange String k Distance Apart	Hard	31.6%	Hash TableHeapGreedy
359	Logger Rate Limiter	Easy	59.9%	Hash TableDesign
341	Flatten Nested List Iterator	Medium	42.1%	StackDesign
346	Moving Average from Data Stream	Easy	59.1%	DesignQueue
348	Design Tic-Tac-Toe	Medium	45.9%	Design
353	Design Snake Game	Medium	26.7%	DesignQueue
380	Insert Delete GetRandom O(1)	Medium	39.3%	ArrayHash TableDesign
381	Insert Delete GetRandom O(1) - Duplicates allowed	Hard	29.0%	ArrayHash TableDesign
389	Find the Difference	Easy	50.9%	Hash TableBit Manipulation
377	Combination Sum IV	Medium	42.2%	Dynamic Programming
376	Wiggle Subsequence	Medium	35.9%	Dynamic ProgrammingGreedy
375	Guess Number Higher or Lower II	Medium	35.8%	Dynamic ProgrammingMinimax
368	Largest Divisible Subset	Medium	33.8%	MathDynamic Programming
363	Max Sum of Rectangle No Larger Than K	Hard	33.3%	Binary SearchDynamic ProgrammingQueue
361	Bomb Enemy	Medium	39.1%	Dynamic Programming
357	Count Numbers with Unique Digits	Medium	46.1%	MathDynamic ProgrammingBacktracking
354	Russian Doll Envelopes	Hard	32.4%	Binary SearchDynamic Programming
381	Insert Delete GetRandom O(1) - Duplicates allowed	Hard	29.0%	ArrayHash TableDesign
351	Android Unlock Patterns	Medium	44.1%	Dynamic ProgrammingBacktracking
343	Integer Break	Medium	46.2%	MathDynamic Programming
338	Counting Bits	Medium	61.6%	Dynamic ProgrammingBit Manipulation
349	Intersection of Two Arrays	Easy	47.5%	Hash TableTwo PointersBinary SearchSort
350	Intersection of Two Arrays II	Easy	44.7%	Hash TableTwo PointersBinary SearchSort
354	Russian Doll Envelopes	Hard	32.4%	Binary SearchDynamic Programming
363	Max Sum of Rectangle No Larger Than K	Hard	33.3%	Binary SearchDynamic ProgrammingQueue
367	Valid Perfect Square	Easy	38.4%	MathBinary Search
349	Intersection of Two Arrays	Easy	47.5%	Hash TableTwo PointersBinary SearchSort
374	Guess Number Higher or Lower	Easy	35.7%	Binary Search
378	Kth Smallest Element in a Sorted Matrix	Medium	45.0%	Binary SearchHeap
392	Is Subsequence	Medium	44.6%	Binary SearchDynamic ProgrammingGreedy
344	Reverse String	Easy	59.5%	Two PointersString
300	Longest Increasing Subsequence	Medium	38.6%	Binary SearchDynamic Programming
356	Line Reflection	Medium	30.1%	Hash TableMath
380	Insert Delete GetRandom O(1)	Medium	39.3%	ArrayHash TableDesign
379	Design Phone Directory	Medium	33.6%	Linked ListDesign
362	Design Hit Counter	Medium	54.3%	Design
366	Find Leaves of Binary Tree	Medium	60.1%	TreeDepth-first Search
364	Nested List Weight Sum II	Medium	52.9%	Depth-first Search
339	Nested List Weight Sum	Easy	62.4%	Depth-first Search
357	Count Numbers with Unique Digits	Medium	46.1%	MathDynamic ProgrammingBacktracking
345	Reverse Vowels of a String	Easy	38.6%	Two PointersString
349	Intersection of Two Arrays	Easy	47.5%	Hash TableTwo PointersBinary SearchSort
350	Intersection of Two Arrays II	Easy	44.7%	Hash TableTwo PointersBinary SearchSort
360	Sort Transformed Array	Medium	44.2%	MathTwo Pointers
360	Sort Transformed Array	Medium	44.2%	MathTwo Pointers
365	Water and Jug Problem	Medium	27.7%	Math
367	Valid Perfect Square	Easy	38.4%	MathBinary Search
368	Largest Divisible Subset	Medium	33.8%	MathDynamic Programming
372	Super Pow	Medium	34.5%	Math
380	Insert Delete GetRandom O(1)	Medium	39.3%	ArrayHash TableDesign
337	House Robber III	Medium	43.9%	TreeDepth-first Search
359	Logger Rate Limiter	Easy	59.9%	Hash TableDesign
347	Top K Frequent Elements	Medium	48.5%	Hash TableHeap
381	Insert Delete GetRandom O(1) - Duplicates allowed	Hard	29.0%	ArrayHash TableDesign
355	Design Twitter	Medium	25.6%	Hash TableHeapDesign
357	Count Numbers with Unique Digits	Medium	46.1%	MathDynamic ProgrammingBacktracking
340	Longest Substring with At Most K Distinct Characters	Hard	39.0%	Hash TableString
451	Sort Characters By Frequency	Medium	51.1%	Hash TableHeap
417	Pacific Atlantic Water Flow	Medium	33.8%	Depth-first SearchBreadth-first Search
411	Minimum Unique Word Abbreviation	Hard	33.0%	BacktrackingBit Manipulation
414	Third Maximum Number	Easy	27.9%	Array
394	Decode String	Medium	41.5%	StackDepth-first Search
415	Add Strings	Easy	41.5%	Math
413	Arithmetic Slices	Medium	54.6%	MathDynamic Programming
400	Nth Digit	Easy	30.0%	Math
416	Partition Equal Subset Sum	Medium	39.3%	Dynamic Programming
413	Arithmetic Slices	Medium	54.6%	MathDynamic Programming
410	Split Array Largest Sum	Hard	38.2%	Binary SearchDynamic Programming
403	Frog Jump	Hard	32.4%	Dynamic Programming
397	Integer Replacement	Medium	30.3%	MathBit Manipulation
396	Rotate Function	Medium	33.3%	Math
409	Longest Palindrome	Easy	45.4%	Hash Table
410	Split Array Largest Sum	Hard	38.2%	Binary SearchDynamic Programming
401	Binary Watch	Easy	44.8%	BacktrackingBit Manipulation
404	Sum of Left Leaves	Easy	47.2%	Tree
448	Find All Numbers Disappeared in an Array	Easy	51.2%	Array
437	Path Sum III	Easy	39.9%	Tree
432	All O`one Data Structure	Hard	28.2%	Design
436	Find Right Interval	Medium	41.4%	Binary Search
423	Reconstruct Original Digits from English	Medium	44.5%	Math
425	Word Squares	Hard	43.1%	BacktrackingTrie
418	Sentence Screen Fitting	Medium	27.8%	Dynamic Programming
450	Delete Node in a BST	Medium	37.1%	Tree
442	Find All Duplicates in an Array	Medium	56.1%	Array
441	Arranging Coins	Easy	36.3%	MathBinary Search
439	Ternary Expression Parser	Medium	51.1%	StackDepth-first Search
441	Arranging Coins	Easy	36.3%	MathBinary Search
438	Find All Anagrams in a String	Easy	33.7%	Hash Table
473	Matchsticks to Square	Medium	35.5%	Depth-first Search
447	Number of Boomerangs	Easy	45.4%	Hash Table
446	Arithmetic Slices II - Subsequence	Hard	27.2%	Dynamic Programming
488	Zuma Game	Hard	37.5%	Depth-first Search
490	The Maze	Medium	43.2%	Depth-first SearchBreadth-first Search
454	4Sum II	Medium	47.2%	Hash TableBinary Search
454	4Sum II	Medium	47.2%	Hash TableBinary Search
462	Minimum Moves to Equal Array Elements II	Medium	51.8%	Math
460	LFU Cache	Hard	24.3%	Design
463	Island Perimeter	Easy	57.3%	Hash Table
469	Convex Polygon	Medium	32.9%	Math
472	Concatenated Words	Hard	30.3%	Dynamic ProgrammingDepth-first SearchTrie
472	Concatenated Words	Hard	30.3%	Dynamic ProgrammingDepth-first SearchTrie
471	Encode String with Shortest Length	Hard	42.5%	Dynamic Programming
464	Can I Win	Medium	25.0%	Dynamic ProgrammingMinimax
466	Count The Repetitions	Hard	28.0%	Dynamic Programming
467	Unique Substrings in Wraparound String	Medium	32.9%	Dynamic Programming
494	Target Sum	Medium	43.4%	Dynamic ProgrammingDepth-first Search
483	Smallest Good Base	Hard	33.3%	MathBinary Search
474	Ones and Zeroes	Medium	38.9%	Dynamic Programming
483	Smallest Good Base	Hard	33.3%	MathBinary Search
475	Heaters	Easy	29.6%	Binary Search
491	Increasing Subsequences	Medium	38.8%	Depth-first Search
486	Predict the Winner	Medium	45.1%	Dynamic ProgrammingMinimax
485	Max Consecutive Ones	Easy	53.9%	Array
300	Longest Increasing Subsequence	Medium	38.6%	Binary SearchDynamic Programming
487	Max Consecutive Ones II	Medium	45.5%	Two Pointers
336	Palindrome Pairs	Hard	26.4%	Hash TableStringTrie
598	Range Addition II	Easy	48.2%	Math
515	Find Largest Value in Each Tree Row	Medium	55.0%	TreeDepth-first SearchBreadth-first Search
505	The Maze II	Medium	37.7%	Depth-first SearchBreadth-first Search
515	Find Largest Value in Each Tree Row	Medium	55.0%	TreeDepth-first SearchBreadth-first Search
513	Find Bottom Left Tree Value	Medium	56.1%	TreeDepth-first SearchBreadth-first Search
514	Freedom Trail	Hard	39.2%	Divide and ConquerDynamic ProgrammingDepth-first Search
499	The Maze III	Hard	32.7%	Depth-first SearchBreadth-first Search
495	Teemo Attacking	Medium	51.5%	Array
513	Find Bottom Left Tree Value	Medium	56.1%	TreeDepth-first SearchBreadth-first Search
508	Most Frequent Subtree Sum	Medium	52.3%	Hash TableTree
500	Keyboard Row	Easy	59.7%	Hash Table
508	Most Frequent Subtree Sum	Medium	52.3%	Hash TableTree
507	Perfect Number	Easy	33.8%	Math
501	Find Mode in Binary Search Tree	Easy	37.7%	Tree
604	Design Compressed String Iterator	Easy	32.4%	Design
582	Kill Process	Medium	49.5%	TreeQueue
562	Longest Line of Consecutive One in Matrix	Medium	40.6%	Array
567	Permutation in String	Medium	36.6%	Two Pointers
535	Encode and Decode TinyURL	Medium	74.2%	Hash TableMath
563	Binary Tree Tilt	Easy	47.1%	Tree
524	Longest Word in Dictionary through Deleting	Medium	42.9%	Two PointersSort
532	K-diff Pairs in an Array	Easy	28.2%	ArrayTwo Pointers
523	Continuous Subarray Sum	Medium	23.0%	MathDynamic Programming
529	Minesweeper	Medium	49.5%	Depth-first SearchBreadth-first Search
531	Lonely Pixel I	Medium	55.3%	ArrayDepth-first Search
535	Encode and Decode TinyURL	Medium	74.2%	Hash TableMath
517	Super Washing Machines	Hard	36.5%	MathDynamic Programming
533	Lonely Pixel II	Medium	44.2%	ArrayDepth-first Search
533	Lonely Pixel II	Medium	44.2%	ArrayDepth-first Search
523	Continuous Subarray Sum	Medium	23.0%	MathDynamic Programming
517	Super Washing Machines	Hard	36.5%	MathDynamic Programming
516	Longest Palindromic Subsequence	Medium	42.7%	Dynamic Programming
526	Beautiful Arrangement	Medium	54.5%	Backtracking
525	Contiguous Array	Medium	40.5%	Hash Table
531	Lonely Pixel I	Medium	55.3%	ArrayDepth-first Search
532	K-diff Pairs in an Array	Easy	28.2%	ArrayTwo Pointers
560	Subarray Sum Equals K	Medium	40.2%	ArrayMap
545	Boundary of Binary Tree	Medium	31.7%	Tree
543	Diameter of Binary Tree	Easy	44.4%	Tree
538	Convert BST to Greater Tree	Easy	49.4%	Tree
537	Complex Number Multiplication	Medium	64.0%	MathString
542	01 Matrix	Medium	33.3%	Depth-first SearchBreadth-first Search
536	Construct Binary Tree from String	Medium	42.6%	StringTree
566	Reshape the Matrix	Easy	58.5%	Array
554	Brick Wall	Medium	45.7%	Hash Table
549	Binary Tree Longest Consecutive Sequence II	Medium	41.3%	Tree
547	Friend Circles	Medium	49.2%	Depth-first SearchUnion Find
552	Student Attendance Record II	Hard	31.4%	Dynamic Programming
548	Split Array with Equal Sum	Medium	36.8%	Array
546	Remove Boxes	Hard	34.0%	Dynamic ProgrammingDepth-first Search
553	Optimal Division	Medium	55.1%	MathString
546	Remove Boxes	Hard	34.0%	Dynamic ProgrammingDepth-first Search
561	Array Partition I	Easy	66.8%	Array
572	Subtree of Another Tree	Easy	40.8%	Tree
576	Out of Boundary Paths	Medium	30.9%	Dynamic ProgrammingDepth-first Search
568	Maximum Vacation Days	Hard	39.9%	Dynamic Programming
576	Out of Boundary Paths	Medium	30.9%	Dynamic ProgrammingDepth-first Search
575	Distribute Candies	Easy	58.7%	Hash Table
581	Shortest Unsorted Continuous Subarray	Easy	29.5%	Array
573	Squirrel Simulation	Medium	52.3%	Math
652	Find Duplicate Subtrees	Medium	34.9%	Tree
606	Construct String from Binary Tree	Easy	49.8%	StringTree
592	Fraction Addition and Subtraction	Medium	46.4%	Math
605	Can Place Flowers	Easy	30.0%	Array
593	Valid Square	Medium	40.0%	Math
588	Design In-Memory File System	Hard	34.7%	Design
599	Minimum Index Sum of Two Lists	Easy	46.3%	Hash Table
600	Non-negative Integers without Consecutive Ones	Hard	30.4%	Dynamic Programming
594	Longest Harmonious Subsequence	Easy	41.1%	Hash Table
656	Coin Path	Hard	24.5%	Dynamic Programming
663	Equal Tree Partition	Medium	36.6%	Tree
638	Shopping Offers	Medium	42.9%	Dynamic ProgrammingDepth-first Search
621	Task Scheduler	Medium	42.1%	ArrayGreedyQueue
642	Design Search Autocomplete System	Hard	30.0%	DesignTrie
639	Decode Ways II	Hard	23.6%	Dynamic Programming
628	Maximum Product of Three Numbers	Easy	45.0%	ArrayMath
637	Average of Levels in Binary Tree	Easy	55.8%	Tree
635	Design Log Storage System	Medium	48.4%	StringDesign
644	Maximum Average Subarray II	Hard	22.1%	ArrayBinary Search
631	Design Excel Sum Formula	Hard	26.6%	Design
629	K Inverse Pairs Array	Hard	26.7%	Dynamic Programming
643	Maximum Average Subarray I	Easy	37.7%	Array
609	Find Duplicate File in System	Medium	52.5%	Hash TableString
624	Maximum Distance in Arrays	Easy	34.1%	ArrayHash Table
611	Valid Triangle Number	Medium	41.7%	Array
617	Merge Two Binary Trees	Easy	67.9%	Tree
634	Find the Derangement of An Array	Medium	33.8%	Math
633	Sum of Square Numbers	Easy	32.2%	Math
628	Maximum Product of Three Numbers	Easy	45.0%	ArrayMath
625	Minimum Factorization	Medium	30.7%	MathRecursion
624	Maximum Distance in Arrays	Easy	34.1%	ArrayHash Table
632	Smallest Range	Hard	42.4%	Hash TableTwo PointersString
623	Add One Row to Tree	Medium	46.6%	Tree
640	Solve the Equation	Medium	39.0%	Math
638	Shopping Offers	Medium	42.9%	Dynamic ProgrammingDepth-first Search
645	Set Mismatch	Easy	40.3%	Hash TableMath
648	Replace Words	Medium	47.7%	Hash TableTrie
662	Maximum Width of Binary Tree	Medium	37.7%	Tree
646	Maximum Length of Pair Chain	Medium	47.7%	Dynamic Programming
661	Image Smoother	Easy	45.8%	Array
645	Set Mismatch	Easy	40.3%	Hash TableMath
658	Find K Closest Elements	Medium	35.7%	Binary Search
660	Remove 9	Hard	47.1%	Math
651	4 Keys Keyboard	Medium	47.9%	MathDynamic ProgrammingGreedy
632	Smallest Range	Hard	42.4%	Hash TableTwo PointersString
653	Two Sum IV - Input is a BST	Easy	50.7%	Tree
654	Maximum Binary Tree	Medium	70.2%	Tree
655	Print Binary Tree	Medium	50.6%	Tree
644	Maximum Average Subarray II	Hard	22.1%	ArrayBinary Search
647	Palindromic Substrings	Medium	55.8%	StringDynamic Programming
651	4 Keys Keyboard	Medium	47.9%	MathDynamic ProgrammingGreedy
650	2 Keys Keyboard	Medium	44.1%	Dynamic Programming
679	24 Game	Hard	38.5%	Depth-first Search
670	Maximum Swap	Medium	38.4%	ArrayMath
670	Maximum Swap	Medium	38.4%	ArrayMath
664	Strange Printer	Hard	31.4%	Dynamic ProgrammingDepth-first Search
664	Strange Printer	Hard	31.4%	Dynamic ProgrammingDepth-first Search
669	Trim a Binary Search Tree	Easy	58.4%	Tree
666	Path Sum IV	Medium	49.4%	Tree
665	Non-decreasing Array	Easy	21.3%	Array
668	Kth Smallest Number in Multiplication Table	Hard	37.0%	Binary Search
667	Beautiful Arrangement II	Medium	51.6%	Array
687	Longest Univalue Path	Easy	32.3%	TreeRecursion
694	Number of Distinct Islands	Medium	43.5%	Hash TableDepth-first Search
674	Longest Continuous Increasing Subsequence	Easy	43.0%	Array
672	Bulb Switcher II	Medium	48.1%	Math
673	Number of Longest Increasing Subsequence	Medium	30.9%	Dynamic Programming
690	Employee Importance	Easy	55.5%	Hash TableDepth-first SearchBreadth-first Search
684	Redundant Connection	Medium	35.8%	TreeUnion FindGraph
683	K Empty Slots	Hard	37.2%	ArrayBinary Search Tree
671	Second Minimum Node In a Binary Tree	Easy	41.9%	Tree
689	Maximum Sum of 3 Non-Overlapping Subarrays	Hard	42.9%	ArrayDynamic Programming
685	Redundant Connection II	Hard	28.8%	TreeDepth-first SearchUnion FindGraph
685	Redundant Connection II	Hard	28.8%	TreeDepth-first SearchUnion FindGraph
692	Top K Frequent Words	Medium	41.1%	Hash TableHeapTrie
676	Implement Magic Dictionary	Medium	50.0%	Hash TableTrie
694	Number of Distinct Islands	Medium	43.5%	Hash TableDepth-first Search
691	Stickers to Spell Word	Hard	31.7%	Dynamic ProgrammingBacktracking
689	Maximum Sum of 3 Non-Overlapping Subarrays	Hard	42.9%	ArrayDynamic Programming
690	Employee Importance	Easy	55.5%	Hash TableDepth-first SearchBreadth-first Search
688	Knight Probability in Chessboard	Medium	38.3%	Dynamic Programming
691	Stickers to Spell Word	Hard	31.7%	Dynamic ProgrammingBacktracking
695	Max Area of Island	Easy	53.3%	ArrayDepth-first Search
695	Max Area of Island	Easy	53.3%	ArrayDepth-first Search
697	Degree of an Array	Easy	48.9%	Array
698	Partition to K Equal Sum Subsets	Medium	34.7%	Dynamic ProgrammingRecursion
711	Number of Distinct Islands II	Hard	26.0%	Hash TableDepth-first Search
711	Number of Distinct Islands II	Hard	26.0%	Hash TableDepth-first Search

Tag:tree

ID	Title	Difficulty	Acceptance	Tags
268	Missing Number	Easy	44.3%	ArrayMathBit Manipulation
208	Implement Trie (Prefix Tree)	Medium	29.1%	DesignTrie
1	Two Sum	Easy	35.6%	ArrayHash Table
4	Median of Two Sorted Arrays	Hard	22.1%	ArrayBinary SearchDivide and Conquer
3	Longest Substring Without Repeating Characters	Medium	24.4%	Hash TableTwo PointersString
2	Add Two Numbers	Medium	28.0%	Linked ListMath
7	Reverse Integer	Easy	24.5%	Math
8	String to Integer (atoi)	Medium	14.0%	MathString
9	Palindrome Number	Easy	35.5%	Math
10	Regular Expression Matching	Hard	24.2%	StringDynamic ProgrammingBacktracking
4	Median of Two Sorted Arrays	Hard	22.1%	ArrayBinary SearchDivide and Conquer
1	Two Sum	Easy	35.6%	ArrayHash Table
3	Longest Substring Without Repeating Characters	Medium	24.4%	Hash TableTwo PointersString
107	Binary Tree Level Order Traversal II	Easy	40.8%	TreeBreadth-first Search
42	Trapping Rain Water	Hard	37.0%	ArrayTwo PointersStack
45	Jump Game II	Hard	26.2%	ArrayGreedy
48	Rotate Image	Medium	39.5%	Array
53	Maximum Subarray	Easy	39.8%	ArrayDivide and ConquerDynamic Programming
54	Spiral Matrix	Medium	26.4%	Array
55	Jump Game	Medium	29.5%	ArrayGreedy
56	Merge Intervals	Medium	30.7%	ArraySort
57	Insert Interval	Hard	28.1%	ArraySort
59	Spiral Matrix II	Medium	40.1%	Array
62	Unique Paths	Medium	41.7%	ArrayDynamic Programming
63	Unique Paths II	Medium	31.9%	ArrayDynamic Programming
64	Minimum Path Sum	Medium	38.9%	ArrayDynamic Programming
66	Plus One	Easy	38.9%	ArrayMath
73	Set Matrix Zeroes	Medium	36.1%	Array
74	Search a 2D Matrix	Medium	34.9%	ArrayBinary Search
75	Sort Colors	Medium	38.3%	ArrayTwo PointersSort
78	Subsets	Medium	41.8%	ArrayBacktrackingBit Manipulation
79	Word Search	Medium	27.2%	ArrayBacktracking
80	Remove Duplicates from Sorted Array II	Medium	36.3%	ArrayTwo Pointers
81	Search in Rotated Sorted Array II	Medium	32.7%	ArrayBinary Search
84	Largest Rectangle in Histogram	Hard	27.0%	ArrayStack
85	Maximal Rectangle	Hard	28.5%	ArrayHash TableDynamic ProgrammingStack
88	Merge Sorted Array	Easy	32.1%	ArrayTwo Pointers
90	Subsets II	Medium	36.9%	ArrayBacktracking
105	Construct Binary Tree from Preorder and Inorder Traversal	Medium	32.6%	ArrayTreeDepth-first Search
106	Construct Binary Tree from Inorder and Postorder Traversal	Medium	32.4%	ArrayTreeDepth-first Search
41	First Missing Positive	Hard	25.6%	Array
40	Combination Sum II	Medium	34.4%	ArrayBacktracking
39	Combination Sum	Medium	39.5%	ArrayBacktracking
35	Search Insert Position	Easy	39.8%	ArrayBinary Search
34	Search for a Range	Medium	31.4%	ArrayBinary Search
33	Search in Rotated Sorted Array	Medium	32.1%	ArrayBinary Search
31	Next Permutation	Medium	28.8%	Array
27	Remove Element	Easy	39.6%	ArrayTwo Pointers
26	Remove Duplicates from Sorted Array	Easy	35.4%	ArrayTwo Pointers
18	4Sum	Medium	27.0%	ArrayHash TableTwo Pointers
16	3Sum Closest	Medium	31.3%	ArrayTwo Pointers
15	3Sum	Medium	21.8%	ArrayTwo Pointers
11	Container With Most Water	Medium	36.8%	ArrayTwo Pointers
98	Validate Binary Search Tree	Medium	23.6%	TreeDepth-first Search
99	Recover Binary Search Tree	Hard	30.2%	TreeDepth-first Search
100	Same Tree	Easy	46.8%	TreeDepth-first Search
101	Symmetric Tree	Easy	39.2%	TreeDepth-first SearchBreadth-first Search
104	Maximum Depth of Binary Tree	Easy	53.1%	TreeDepth-first Search
105	Construct Binary Tree from Preorder and Inorder Traversal	Medium	32.6%	ArrayTreeDepth-first Search
106	Construct Binary Tree from Inorder and Postorder Traversal	Medium	32.4%	ArrayTreeDepth-first Search
94	Binary Tree Inorder Traversal	Medium	47.4%	Hash TableStackTree
85	Maximal Rectangle	Hard	28.5%	ArrayHash TableDynamic ProgrammingStack
76	Minimum Window Substring	Hard	25.9%	Hash TableTwo PointersString
49	Group Anagrams	Medium	35.9%	Hash TableString
37	Sudoku Solver	Hard	30.8%	Hash TableBacktracking
36	Valid Sudoku	Medium	36.3%	Hash Table
30	Substring with Concatenation of All Words	Hard	22.0%	Hash TableTwo PointersString
18	4Sum	Medium	27.0%	ArrayHash TableTwo Pointers
32	Longest Valid Parentheses	Hard	23.1%	StringDynamic Programming
44	Wildcard Matching	Hard	20.4%	StringDynamic ProgrammingBacktrackingGreedy
53	Maximum Subarray	Easy	39.8%	ArrayDivide and ConquerDynamic Programming
62	Unique Paths	Medium	41.7%	ArrayDynamic Programming
63	Unique Paths II	Medium	31.9%	ArrayDynamic Programming
64	Minimum Path Sum	Medium	38.9%	ArrayDynamic Programming
70	Climbing Stairs	Easy	40.3%	Dynamic Programming
108	Convert Sorted Array to Binary Search Tree	Easy	42.5%	TreeDepth-first Search
109	Convert Sorted List to Binary Search Tree	Medium	34.4%	Linked ListDepth-first Search
110	Balanced Binary Tree	Easy	37.8%	TreeDepth-first Search
111	Minimum Depth of Binary Tree	Easy	33.3%	TreeDepth-first SearchBreadth-first Search
112	Path Sum	Easy	34.2%	TreeDepth-first Search
113	Path Sum II	Medium	34.3%	TreeDepth-first Search
114	Flatten Binary Tree to Linked List	Medium	35.5%	TreeDepth-first Search
116	Populating Next Right Pointers in Each Node	Medium	36.9%	TreeDepth-first Search
11	Container With Most Water	Medium	36.8%	ArrayTwo Pointers
15	3Sum	Medium	21.8%	ArrayTwo Pointers
16	3Sum Closest	Medium	31.3%	ArrayTwo Pointers
18	4Sum	Medium	27.0%	ArrayHash TableTwo Pointers
19	Remove Nth Node From End of List	Medium	33.8%	Linked ListTwo Pointers
26	Remove Duplicates from Sorted Array	Easy	35.4%	ArrayTwo Pointers
27	Remove Element	Easy	39.6%	ArrayTwo Pointers
28	Implement strStr()	Easy	28.4%	Two PointersString
30	Substring with Concatenation of All Words	Hard	22.0%	Hash TableTwo PointersString
42	Trapping Rain Water	Hard	37.0%	ArrayTwo PointersStack
61	Rotate List	Medium	24.3%	Linked ListTwo Pointers
75	Sort Colors	Medium	38.3%	ArrayTwo PointersSort
76	Minimum Window Substring	Hard	25.9%	Hash TableTwo PointersString
80	Remove Duplicates from Sorted Array II	Medium	36.3%	ArrayTwo Pointers
86	Partition List	Medium	33.0%	Linked ListTwo Pointers
88	Merge Sorted Array	Easy	32.1%	ArrayTwo Pointers
94	Binary Tree Inorder Traversal	Medium	47.4%	Hash TableStackTree
95	Unique Binary Search Trees II	Medium	31.7%	Dynamic ProgrammingTree
96	Unique Binary Search Trees	Medium	41.3%	Dynamic ProgrammingTree
72	Edit Distance	Hard	32.0%	StringDynamic Programming
85	Maximal Rectangle	Hard	28.5%	ArrayHash TableDynamic ProgrammingStack
87	Scramble String	Hard	29.4%	StringDynamic Programming
98	Validate Binary Search Tree	Medium	23.6%	TreeDepth-first Search
99	Recover Binary Search Tree	Hard	30.2%	TreeDepth-first Search
100	Same Tree	Easy	46.8%	TreeDepth-first Search
101	Symmetric Tree	Easy	39.2%	TreeDepth-first SearchBreadth-first Search
102	Binary Tree Level Order Traversal	Medium	40.6%	TreeBreadth-first Search
103	Binary Tree Zigzag Level Order Traversal	Medium	35.2%	StackTreeBreadth-first Search
104	Maximum Depth of Binary Tree	Easy	53.1%	TreeDepth-first Search
105	Construct Binary Tree from Preorder and Inorder Traversal	Medium	32.6%	ArrayTreeDepth-first Search
106	Construct Binary Tree from Inorder and Postorder Traversal	Medium	32.4%	ArrayTreeDepth-first Search
108	Convert Sorted Array to Binary Search Tree	Easy	42.5%	TreeDepth-first Search
110	Balanced Binary Tree	Easy	37.8%	TreeDepth-first Search
111	Minimum Depth of Binary Tree	Easy	33.3%	TreeDepth-first SearchBreadth-first Search
112	Path Sum	Easy	34.2%	TreeDepth-first Search
113	Path Sum II	Medium	34.3%	TreeDepth-first Search
114	Flatten Binary Tree to Linked List	Medium	35.5%	TreeDepth-first Search
10	Regular Expression Matching	Hard	24.2%	StringDynamic ProgrammingBacktracking
12	Integer to Roman	Medium	45.3%	MathString
13	Roman to Integer	Easy	46.4%	MathString
29	Divide Two Integers	Medium	15.9%	MathBinary Search
43	Multiply Strings	Medium	27.5%	MathString
50	Pow(x, n)	Medium	26.1%	MathBinary Search
60	Permutation Sequence	Medium	28.9%	MathBacktracking
65	Valid Number	Hard	12.8%	MathString
66	Plus One	Easy	38.9%	ArrayMath
67	Add Binary	Easy	33.0%	MathString
69	Sqrt(x)	Easy	28.0%	MathBinary Search
115	Distinct Subsequences	Hard	31.7%	StringDynamic Programming
97	Interleaving String	Hard	24.8%	StringDynamic Programming
96	Unique Binary Search Trees	Medium	41.3%	Dynamic ProgrammingTree
81	Search in Rotated Sorted Array II	Medium	32.7%	ArrayBinary Search
74	Search a 2D Matrix	Medium	34.9%	ArrayBinary Search
69	Sqrt(x)	Easy	28.0%	MathBinary Search
50	Pow(x, n)	Medium	26.1%	MathBinary Search
35	Search Insert Position	Easy	39.8%	ArrayBinary Search
34	Search for a Range	Medium	31.4%	ArrayBinary Search
33	Search in Rotated Sorted Array	Medium	32.1%	ArrayBinary Search
29	Divide Two Integers	Medium	15.9%	MathBinary Search
91	Decode Ways	Medium	19.9%	StringDynamic Programming
95	Unique Binary Search Trees II	Medium	31.7%	Dynamic ProgrammingTree
17	Letter Combinations of a Phone Number	Medium	35.1%	StringBacktracking
22	Generate Parentheses	Medium	45.9%	StringBacktracking
37	Sudoku Solver	Hard	30.8%	Hash TableBacktracking
39	Combination Sum	Medium	39.5%	ArrayBacktracking
40	Combination Sum II	Medium	34.4%	ArrayBacktracking
44	Wildcard Matching	Hard	20.4%	StringDynamic ProgrammingBacktrackingGreedy
46	Permutations	Medium	44.8%	Backtracking
47	Permutations II	Medium	33.4%	Backtracking
51	N-Queens	Hard	31.7%	Backtracking
52	N-Queens II	Hard	45.5%	Backtracking
60	Permutation Sequence	Medium	28.9%	MathBacktracking
77	Combinations	Medium	40.2%	Backtracking
78	Subsets	Medium	41.8%	ArrayBacktrackingBit Manipulation
79	Word Search	Medium	27.2%	ArrayBacktracking
89	Gray Code	Medium	41.6%	Backtracking
90	Subsets II	Medium	36.9%	ArrayBacktracking
93	Restore IP Addresses	Medium	27.7%	StringBacktracking
167	Two Sum II - Input array is sorted	Easy	47.1%	ArrayTwo PointersBinary Search
159	Longest Substring with At Most Two Distinct Characters	Hard	41.6%	Hash TableTwo PointersString
118	Pascal's Triangle	Easy	39.0%	Array
119	Pascal's Triangle II	Easy	37.3%	Array
120	Triangle	Medium	34.1%	ArrayDynamic Programming
121	Best Time to Buy and Sell Stock	Easy	41.7%	ArrayDynamic Programming
122	Best Time to Buy and Sell Stock II	Easy	47.4%	ArrayGreedy
123	Best Time to Buy and Sell Stock III	Hard	29.6%	ArrayDynamic Programming
126	Word Ladder II	Hard	14.4%	ArrayStringBacktrackingBreadth-first Search
117	Populating Next Right Pointers in Each Node II	Medium	33.8%	TreeDepth-first Search
124	Binary Tree Maximum Path Sum	Hard	26.4%	TreeDepth-first Search
125	Valid Palindrome	Easy	26.5%	Two PointersString
117	Populating Next Right Pointers in Each Node II	Medium	33.8%	TreeDepth-first Search
124	Binary Tree Maximum Path Sum	Hard	26.4%	TreeDepth-first Search
123	Best Time to Buy and Sell Stock III	Hard	29.6%	ArrayDynamic Programming
121	Best Time to Buy and Sell Stock	Easy	41.7%	ArrayDynamic Programming
120	Triangle	Medium	34.1%	ArrayDynamic Programming
162	Find Peak Element	Medium	37.9%	ArrayBinary Search
153	Find Minimum in Rotated Sorted Array	Medium	40.2%	ArrayBinary Search
140	Word Break II	Hard	23.6%	Dynamic ProgrammingBacktracking
128	Longest Consecutive Sequence	Hard	37.3%	ArrayUnion Find
152	Maximum Product Subarray	Medium	26.0%	ArrayDynamic Programming
153	Find Minimum in Rotated Sorted Array	Medium	40.2%	ArrayBinary Search
132	Palindrome Partitioning II	Hard	24.4%	Dynamic Programming
139	Word Break	Medium	30.4%	Dynamic Programming
140	Word Break II	Hard	23.6%	Dynamic ProgrammingBacktracking
152	Maximum Product Subarray	Medium	26.0%	ArrayDynamic Programming
149	Max Points on a Line	Hard	15.3%	Hash TableMath
138	Copy List with Random Pointer	Medium	26.1%	Hash TableLinked List
136	Single Number	Easy	54.8%	Hash TableBit Manipulation
129	Sum Root to Leaf Numbers	Medium	37.0%	TreeDepth-first Search
133	Clone Graph	Medium	25.1%	Depth-first SearchBreadth-first SearchGraph
131	Palindrome Partitioning	Medium	34.0%	Backtracking
141	Linked List Cycle	Easy	35.3%	Linked ListTwo Pointers
142	Linked List Cycle II	Medium	30.9%	Linked ListTwo Pointers
146	LRU Cache	Hard	18.4%	Design
129	Sum Root to Leaf Numbers	Medium	37.0%	TreeDepth-first Search
144	Binary Tree Preorder Traversal	Medium	45.5%	StackTree
145	Binary Tree Postorder Traversal	Hard	40.6%	StackTree
149	Max Points on a Line	Hard	15.3%	Hash TableMath
173	Binary Search Tree Iterator	Medium	42.0%	StackTreeDesign
199	Binary Tree Right Side View	Medium	41.5%	TreeDepth-first SearchBreadth-first Search
116	Populating Next Right Pointers in Each Node	Medium	36.9%	TreeDepth-first Search
156	Binary Tree Upside Down	Medium	44.9%	Tree
173	Binary Search Tree Iterator	Medium	42.0%	StackTreeDesign
199	Binary Tree Right Side View	Medium	41.5%	TreeDepth-first SearchBreadth-first Search
170	Two Sum III - Data structure design	Easy	25.0%	Hash TableDesign
202	Happy Number	Easy	40.9%	Hash TableMath
187	Repeated DNA Sequences	Medium	32.0%	Hash TableBit Manipulation
200	Number of Islands	Medium	35.2%	Depth-first SearchBreadth-first SearchUnion Find
207	Course Schedule	Medium	32.6%	Depth-first SearchBreadth-first SearchGraphTopological Sort
170	Two Sum III - Data structure design	Easy	25.0%	Hash TableDesign
166	Fraction to Recurring Decimal	Medium	17.7%	Hash TableMath
159	Longest Substring with At Most Two Distinct Characters	Hard	41.6%	Hash TableTwo PointersString
154	Find Minimum in Rotated Sorted Array II	Hard	37.4%	ArrayBinary Search
174	Dungeon Game	Hard	23.9%	Binary SearchDynamic Programming
204	Count Primes	Easy	26.7%	Hash TableMath
205	Isomorphic Strings	Easy	34.1%	Hash Table
188	Best Time to Buy and Sell Stock IV	Hard	24.4%	Dynamic Programming
198	House Robber	Easy	39.3%	Dynamic Programming
154	Find Minimum in Rotated Sorted Array II	Hard	37.4%	ArrayBinary Search
126	Word Ladder II	Hard	14.4%	ArrayStringBacktrackingBreadth-first Search
162	Find Peak Element	Medium	37.9%	ArrayBinary Search
163	Missing Ranges	Medium	23.9%	Array
167	Two Sum II - Input array is sorted	Easy	47.1%	ArrayTwo PointersBinary Search
169	Majority Element	Easy	47.0%	ArrayDivide and ConquerBit Manipulation
189	Rotate Array	Easy	24.9%	Array
155	Min Stack	Easy	29.3%	StackDesign
174	Dungeon Game	Hard	23.9%	Binary SearchDynamic Programming
167	Two Sum II - Input array is sorted	Easy	47.1%	ArrayTwo PointersBinary Search
166	Fraction to Recurring Decimal	Medium	17.7%	Hash TableMath
168	Excel Sheet Column Title	Easy	26.5%	Math
171	Excel Sheet Column Number	Easy	47.6%	Math
172	Factorial Trailing Zeroes	Easy	36.3%	Math
202	Happy Number	Easy	40.9%	Hash TableMath
204	Count Primes	Easy	26.7%	Hash TableMath
397	Integer Replacement	Medium	30.3%	MathBit Manipulation
223	Rectangle Area	Medium	33.2%	Math
209	Minimum Size Subarray Sum	Medium	31.2%	ArrayTwo PointersBinary Search
221	Maximal Square	Medium	29.4%	Dynamic Programming
213	House Robber II	Medium	34.2%	Dynamic Programming
211	Add and Search Word - Data structure design	Medium	23.7%	BacktrackingDesignTrie
222	Count Complete Tree Nodes	Medium	27.6%	Binary SearchTree
210	Course Schedule II	Medium	28.7%	Depth-first SearchBreadth-first SearchGraphTopological Sort
209	Minimum Size Subarray Sum	Medium	31.2%	ArrayTwo PointersBinary Search
222	Count Complete Tree Nodes	Medium	27.6%	Binary SearchTree
217	Contains Duplicate	Easy	46.1%	ArrayHash Table
219	Contains Duplicate II	Easy	32.6%	ArrayHash Table
211	Add and Search Word - Data structure design	Medium	23.7%	BacktrackingDesignTrie
212	Word Search II	Hard	23.7%	BacktrackingTrie
216	Combination Sum III	Medium	45.8%	ArrayBacktracking
219	Contains Duplicate II	Easy	32.6%	ArrayHash Table
209	Minimum Size Subarray Sum	Medium	31.2%	ArrayTwo PointersBinary Search
216	Combination Sum III	Medium	45.8%	ArrayBacktracking
217	Contains Duplicate	Easy	46.1%	ArrayHash Table
436	Find Right Interval	Medium	41.4%	Binary Search
276	Paint Fence	Easy	34.6%	Dynamic Programming
258	Add Digits	Easy	51.4%	Math
265	Paint House II	Hard	38.0%	Dynamic Programming
264	Ugly Number II	Medium	32.9%	MathDynamic ProgrammingHeap
256	Paint House	Easy	46.2%	Dynamic Programming
263	Ugly Number	Easy	39.4%	Math
264	Ugly Number II	Medium	32.9%	MathDynamic ProgrammingHeap
268	Missing Number	Easy	44.3%	ArrayMathBit Manipulation
273	Integer to English Words	Hard	22.3%	MathString
224	Basic Calculator	Hard	27.5%	MathStack
259	3Sum Smaller	Medium	41.6%	ArrayTwo Pointers
228	Summary Ranges	Medium	30.5%	Array
234	Palindrome Linked List	Easy	33.0%	Linked ListTwo Pointers
267	Palindrome Permutation II	Medium	31.9%	Backtracking
254	Factor Combinations	Medium	43.0%	Backtracking
231	Power of Two	Easy	40.3%	MathBit Manipulation
275	H-Index II	Medium	34.6%	Binary Search
270	Closest Binary Search Tree Value	Easy	39.9%	Binary SearchTree
229	Majority Element II	Medium	28.7%	Array
240	Search a 2D Matrix II	Medium	38.7%	Binary SearchDivide and Conquer
230	Kth Smallest Element in a BST	Medium	44.2%	Binary SearchTree
238	Product of Array Except Self	Medium	49.6%	Array
243	Shortest Word Distance	Easy	52.8%	Array
245	Shortest Word Distance III	Medium	50.6%	Array
261	Graph Valid Tree	Medium	38.0%	Depth-first SearchBreadth-first SearchUnion FindGraph
257	Binary Tree Paths	Easy	39.3%	TreeDepth-first Search
248	Strobogrammatic Number III	Hard	32.1%	MathRecursion
244	Shortest Word Distance II	Medium	38.9%	Hash TableDesign
246	Strobogrammatic Number	Easy	40.0%	Hash TableMath
233	Number of Digit One	Hard	28.6%	Math
246	Strobogrammatic Number	Easy	40.0%	Hash TableMath
242	Valid Anagram	Easy	46.7%	Hash TableSort
225	Implement Stack using Queues	Easy	33.3%	StackDesign
232	Implement Queue using Stacks	Easy	37.2%	StackDesign
251	Flatten 2D Vector	Medium	40.8%	Design
249	Group Shifted Strings	Medium	42.2%	Hash TableString
259	3Sum Smaller	Medium	41.6%	ArrayTwo Pointers
244	Shortest Word Distance II	Medium	38.9%	Hash TableDesign
272	Closest Binary Search Tree Value II	Hard	39.3%	StackTree
270	Closest Binary Search Tree Value	Easy	39.9%	Binary SearchTree
257	Binary Tree Paths	Easy	39.3%	TreeDepth-first Search
255	Verify Preorder Sequence in Binary Search Tree	Medium	40.5%	StackTree
250	Count Univalue Subtrees	Medium	42.5%	Tree
236	Lowest Common Ancestor of a Binary Tree	Medium	30.0%	Tree
235	Lowest Common Ancestor of a Binary Search Tree	Easy	39.3%	Tree
230	Kth Smallest Element in a BST	Medium	44.2%	Binary SearchTree
226	Invert Binary Tree	Easy	52.3%	Tree
247	Strobogrammatic Number II	Medium	40.3%	MathRecursion
266	Palindrome Permutation	Easy	57.3%	Hash Table
274	H-Index	Medium	33.4%	Hash TableSort
467	Unique Substrings in Wraparound String	Medium	32.9%	Dynamic Programming
288	Unique Word Abbreviation	Medium	17.0%	Hash TableDesign
281	Zigzag Iterator	Medium	51.1%	Design
284	Peeking Iterator	Medium	35.5%	Design
283	Move Zeroes	Easy	50.4%	ArrayTwo Pointers
287	Find the Duplicate Number	Medium	43.7%	ArrayTwo PointersBinary Search
285	Inorder Successor in BST	Medium	36.2%	Tree
279	Perfect Squares	Medium	37.3%	MathDynamic ProgrammingBreadth-first Search
288	Unique Word Abbreviation	Medium	17.0%	Hash TableDesign
277	Find the Celebrity	Medium	35.6%	Array
279	Perfect Squares	Medium	37.3%	MathDynamic ProgrammingBreadth-first Search
280	Wiggle Sort	Medium	57.6%	ArraySort
278	First Bad Version	Easy	25.6%	Binary Search
287	Find the Duplicate Number	Medium	43.7%	ArrayTwo PointersBinary Search
287	Find the Duplicate Number	Medium	43.7%	ArrayTwo PointersBinary Search
283	Move Zeroes	Easy	50.4%	ArrayTwo Pointers
485	Max Consecutive Ones	Easy	53.9%	Array
291	Word Pattern II	Hard	38.0%	Backtracking
290	Word Pattern	Easy	33.2%	Hash Table
289	Game of Life	Medium	37.1%	Array
487	Max Consecutive Ones II	Medium	45.5%	Two Pointers
297	Serialize and Deserialize Binary Tree	Hard	33.8%	TreeDesign
295	Find Median from Data Stream	Hard	27.5%	HeapDesign
297	Serialize and Deserialize Binary Tree	Hard	33.8%	TreeDesign
296	Best Meeting Point	Hard	51.9%	MathSort
294	Flip Game II	Medium	46.5%	Backtracking
515	Find Largest Value in Each Tree Row	Medium	55.0%	TreeDepth-first SearchBreadth-first Search
494	Target Sum	Medium	43.4%	Dynamic ProgrammingDepth-first Search
325	Maximum Size Subarray Sum Equals k	Medium	42.8%	Hash Table
314	Binary Tree Vertical Order Traversal	Medium	37.1%	Hash Table
311	Sparse Matrix Multiplication	Medium	51.3%	Hash Table
301	Remove Invalid Parentheses	Hard	35.3%	Depth-first SearchBreadth-first Search
323	Number of Connected Components in an Undirected Graph	Medium	48.2%	Depth-first SearchBreadth-first SearchUnion FindGraph
329	Longest Increasing Path in a Matrix	Hard	36.7%	Depth-first SearchTopological SortMemoization
332	Reconstruct Itinerary	Medium	29.4%	Depth-first SearchGraph
335	Self Crossing	Hard	25.6%	Math
326	Power of Three	Easy	40.4%	Math
319	Bulb Switcher	Medium	42.6%	MathBrainteaser
313	Super Ugly Number	Medium	37.9%	MathHeap
303	Range Sum Query - Immutable	Easy	30.4%	Dynamic Programming
304	Range Sum Query 2D - Immutable	Medium	25.8%	Dynamic Programming
309	Best Time to Buy and Sell Stock with Cooldown	Medium	41.1%	Dynamic Programming
312	Burst Balloons	Hard	43.0%	Divide and ConquerDynamic Programming
321	Create Maximum Number	Hard	24.6%	Dynamic ProgrammingGreedy
322	Coin Change	Medium	26.7%	Dynamic Programming
333	Largest BST Subtree	Medium	30.5%	Tree
302	Smallest Rectangle Enclosing Black Pixels	Hard	45.7%	Binary Search
449	Serialize and Deserialize BST	Medium	42.5%	Tree
392	Is Subsequence	Medium	44.6%	Binary SearchDynamic ProgrammingGreedy
350	Intersection of Two Arrays II	Easy	44.7%	Hash TableTwo PointersBinary SearchSort
355	Design Twitter	Medium	25.6%	Hash TableHeapDesign
356	Line Reflection	Medium	30.1%	Hash TableMath
351	Android Unlock Patterns	Medium	44.1%	Dynamic ProgrammingBacktracking
337	House Robber III	Medium	43.9%	TreeDepth-first Search
366	Find Leaves of Binary Tree	Medium	60.1%	TreeDepth-first Search
370	Range Addition	Medium	56.2%	Array
358	Rearrange String k Distance Apart	Hard	31.6%	Hash TableHeapGreedy
359	Logger Rate Limiter	Easy	59.9%	Hash TableDesign
341	Flatten Nested List Iterator	Medium	42.1%	StackDesign
346	Moving Average from Data Stream	Easy	59.1%	DesignQueue
348	Design Tic-Tac-Toe	Medium	45.9%	Design
353	Design Snake Game	Medium	26.7%	DesignQueue
380	Insert Delete GetRandom O(1)	Medium	39.3%	ArrayHash TableDesign
381	Insert Delete GetRandom O(1) - Duplicates allowed	Hard	29.0%	ArrayHash TableDesign
389	Find the Difference	Easy	50.9%	Hash TableBit Manipulation
377	Combination Sum IV	Medium	42.2%	Dynamic Programming
376	Wiggle Subsequence	Medium	35.9%	Dynamic ProgrammingGreedy
375	Guess Number Higher or Lower II	Medium	35.8%	Dynamic ProgrammingMinimax
368	Largest Divisible Subset	Medium	33.8%	MathDynamic Programming
363	Max Sum of Rectangle No Larger Than K	Hard	33.3%	Binary SearchDynamic ProgrammingQueue
361	Bomb Enemy	Medium	39.1%	Dynamic Programming
357	Count Numbers with Unique Digits	Medium	46.1%	MathDynamic ProgrammingBacktracking
354	Russian Doll Envelopes	Hard	32.4%	Binary SearchDynamic Programming
381	Insert Delete GetRandom O(1) - Duplicates allowed	Hard	29.0%	ArrayHash TableDesign
351	Android Unlock Patterns	Medium	44.1%	Dynamic ProgrammingBacktracking
343	Integer Break	Medium	46.2%	MathDynamic Programming
338	Counting Bits	Medium	61.6%	Dynamic ProgrammingBit Manipulation
349	Intersection of Two Arrays	Easy	47.5%	Hash TableTwo PointersBinary SearchSort
350	Intersection of Two Arrays II	Easy	44.7%	Hash TableTwo PointersBinary SearchSort
354	Russian Doll Envelopes	Hard	32.4%	Binary SearchDynamic Programming
363	Max Sum of Rectangle No Larger Than K	Hard	33.3%	Binary SearchDynamic ProgrammingQueue
367	Valid Perfect Square	Easy	38.4%	MathBinary Search
349	Intersection of Two Arrays	Easy	47.5%	Hash TableTwo PointersBinary SearchSort
374	Guess Number Higher or Lower	Easy	35.7%	Binary Search
378	Kth Smallest Element in a Sorted Matrix	Medium	45.0%	Binary SearchHeap
392	Is Subsequence	Medium	44.6%	Binary SearchDynamic ProgrammingGreedy
344	Reverse String	Easy	59.5%	Two PointersString
300	Longest Increasing Subsequence	Medium	38.6%	Binary SearchDynamic Programming
356	Line Reflection	Medium	30.1%	Hash TableMath
380	Insert Delete GetRandom O(1)	Medium	39.3%	ArrayHash TableDesign
379	Design Phone Directory	Medium	33.6%	Linked ListDesign
362	Design Hit Counter	Medium	54.3%	Design
366	Find Leaves of Binary Tree	Medium	60.1%	TreeDepth-first Search
364	Nested List Weight Sum II	Medium	52.9%	Depth-first Search
339	Nested List Weight Sum	Easy	62.4%	Depth-first Search
357	Count Numbers with Unique Digits	Medium	46.1%	MathDynamic ProgrammingBacktracking
345	Reverse Vowels of a String	Easy	38.6%	Two PointersString
349	Intersection of Two Arrays	Easy	47.5%	Hash TableTwo PointersBinary SearchSort
350	Intersection of Two Arrays II	Easy	44.7%	Hash TableTwo PointersBinary SearchSort
360	Sort Transformed Array	Medium	44.2%	MathTwo Pointers
360	Sort Transformed Array	Medium	44.2%	MathTwo Pointers
365	Water and Jug Problem	Medium	27.7%	Math
367	Valid Perfect Square	Easy	38.4%	MathBinary Search
368	Largest Divisible Subset	Medium	33.8%	MathDynamic Programming
372	Super Pow	Medium	34.5%	Math
380	Insert Delete GetRandom O(1)	Medium	39.3%	ArrayHash TableDesign
337	House Robber III	Medium	43.9%	TreeDepth-first Search
359	Logger Rate Limiter	Easy	59.9%	Hash TableDesign
347	Top K Frequent Elements	Medium	48.5%	Hash TableHeap
381	Insert Delete GetRandom O(1) - Duplicates allowed	Hard	29.0%	ArrayHash TableDesign
355	Design Twitter	Medium	25.6%	Hash TableHeapDesign
357	Count Numbers with Unique Digits	Medium	46.1%	MathDynamic ProgrammingBacktracking
340	Longest Substring with At Most K Distinct Characters	Hard	39.0%	Hash TableString
451	Sort Characters By Frequency	Medium	51.1%	Hash TableHeap
417	Pacific Atlantic Water Flow	Medium	33.8%	Depth-first SearchBreadth-first Search
411	Minimum Unique Word Abbreviation	Hard	33.0%	BacktrackingBit Manipulation
414	Third Maximum Number	Easy	27.9%	Array
394	Decode String	Medium	41.5%	StackDepth-first Search
415	Add Strings	Easy	41.5%	Math
413	Arithmetic Slices	Medium	54.6%	MathDynamic Programming
400	Nth Digit	Easy	30.0%	Math
416	Partition Equal Subset Sum	Medium	39.3%	Dynamic Programming
413	Arithmetic Slices	Medium	54.6%	MathDynamic Programming
410	Split Array Largest Sum	Hard	38.2%	Binary SearchDynamic Programming
403	Frog Jump	Hard	32.4%	Dynamic Programming
453	Minimum Moves to Equal Array Elements	Easy	47.5%	Math
396	Rotate Function	Medium	33.3%	Math
409	Longest Palindrome	Easy	45.4%	Hash Table
410	Split Array Largest Sum	Hard	38.2%	Binary SearchDynamic Programming
401	Binary Watch	Easy	44.8%	BacktrackingBit Manipulation
404	Sum of Left Leaves	Easy	47.2%	Tree
448	Find All Numbers Disappeared in an Array	Easy	51.2%	Array
437	Path Sum III	Easy	39.9%	Tree
432	All O`one Data Structure	Hard	28.2%	Design
299	Bulls and Cows	Medium	35.2%	Hash Table
423	Reconstruct Original Digits from English	Medium	44.5%	Math
425	Word Squares	Hard	43.1%	BacktrackingTrie
418	Sentence Screen Fitting	Medium	27.8%	Dynamic Programming
450	Delete Node in a BST	Medium	37.1%	Tree
442	Find All Duplicates in an Array	Medium	56.1%	Array
441	Arranging Coins	Easy	36.3%	MathBinary Search
439	Ternary Expression Parser	Medium	51.1%	StackDepth-first Search
441	Arranging Coins	Easy	36.3%	MathBinary Search
438	Find All Anagrams in a String	Easy	33.7%	Hash Table
473	Matchsticks to Square	Medium	35.5%	Depth-first Search
447	Number of Boomerangs	Easy	45.4%	Hash Table
446	Arithmetic Slices II - Subsequence	Hard	27.2%	Dynamic Programming
488	Zuma Game	Hard	37.5%	Depth-first Search
490	The Maze	Medium	43.2%	Depth-first SearchBreadth-first Search
454	4Sum II	Medium	47.2%	Hash TableBinary Search
454	4Sum II	Medium	47.2%	Hash TableBinary Search
462	Minimum Moves to Equal Array Elements II	Medium	51.8%	Math
460	LFU Cache	Hard	24.3%	Design
463	Island Perimeter	Easy	57.3%	Hash Table
469	Convex Polygon	Medium	32.9%	Math
472	Concatenated Words	Hard	30.3%	Dynamic ProgrammingDepth-first SearchTrie
472	Concatenated Words	Hard	30.3%	Dynamic ProgrammingDepth-first SearchTrie
471	Encode String with Shortest Length	Hard	42.5%	Dynamic Programming
464	Can I Win	Medium	25.0%	Dynamic ProgrammingMinimax
466	Count The Repetitions	Hard	28.0%	Dynamic Programming
320	Generalized Abbreviation	Medium	45.2%	BacktrackingBit Manipulation
494	Target Sum	Medium	43.4%	Dynamic ProgrammingDepth-first Search
483	Smallest Good Base	Hard	33.3%	MathBinary Search
474	Ones and Zeroes	Medium	38.9%	Dynamic Programming
483	Smallest Good Base	Hard	33.3%	MathBinary Search
475	Heaters	Easy	29.6%	Binary Search
491	Increasing Subsequences	Medium	38.8%	Depth-first Search
486	Predict the Winner	Medium	45.1%	Dynamic ProgrammingMinimax
343	Integer Break	Medium	46.2%	MathDynamic Programming
300	Longest Increasing Subsequence	Medium	38.6%	Binary SearchDynamic Programming
298	Binary Tree Longest Consecutive Sequence	Medium	41.2%	Tree
336	Palindrome Pairs	Hard	26.4%	Hash TableStringTrie
639	Decode Ways II	Hard	23.6%	Dynamic Programming
598	Range Addition II	Easy	48.2%	Math
505	The Maze II	Medium	37.7%	Depth-first SearchBreadth-first Search
515	Find Largest Value in Each Tree Row	Medium	55.0%	TreeDepth-first SearchBreadth-first Search
513	Find Bottom Left Tree Value	Medium	56.1%	TreeDepth-first SearchBreadth-first Search
514	Freedom Trail	Hard	39.2%	Divide and ConquerDynamic ProgrammingDepth-first Search
499	The Maze III	Hard	32.7%	Depth-first SearchBreadth-first Search
495	Teemo Attacking	Medium	51.5%	Array
513	Find Bottom Left Tree Value	Medium	56.1%	TreeDepth-first SearchBreadth-first Search
508	Most Frequent Subtree Sum	Medium	52.3%	Hash TableTree
500	Keyboard Row	Easy	59.7%	Hash Table
508	Most Frequent Subtree Sum	Medium	52.3%	Hash TableTree
507	Perfect Number	Easy	33.8%	Math
501	Find Mode in Binary Search Tree	Easy	37.7%	Tree
514	Freedom Trail	Hard	39.2%	Divide and ConquerDynamic ProgrammingDepth-first Search
582	Kill Process	Medium	49.5%	TreeQueue
562	Longest Line of Consecutive One in Matrix	Medium	40.6%	Array
567	Permutation in String	Medium	36.6%	Two Pointers
535	Encode and Decode TinyURL	Medium	74.2%	Hash TableMath
563	Binary Tree Tilt	Easy	47.1%	Tree
524	Longest Word in Dictionary through Deleting	Medium	42.9%	Two PointersSort
532	K-diff Pairs in an Array	Easy	28.2%	ArrayTwo Pointers
523	Continuous Subarray Sum	Medium	23.0%	MathDynamic Programming
529	Minesweeper	Medium	49.5%	Depth-first SearchBreadth-first Search
531	Lonely Pixel I	Medium	55.3%	ArrayDepth-first Search
535	Encode and Decode TinyURL	Medium	74.2%	Hash TableMath
517	Super Washing Machines	Hard	36.5%	MathDynamic Programming
533	Lonely Pixel II	Medium	44.2%	ArrayDepth-first Search
533	Lonely Pixel II	Medium	44.2%	ArrayDepth-first Search
523	Continuous Subarray Sum	Medium	23.0%	MathDynamic Programming
517	Super Washing Machines	Hard	36.5%	MathDynamic Programming
516	Longest Palindromic Subsequence	Medium	42.7%	Dynamic Programming
526	Beautiful Arrangement	Medium	54.5%	Backtracking
525	Contiguous Array	Medium	40.5%	Hash Table
531	Lonely Pixel I	Medium	55.3%	ArrayDepth-first Search
532	K-diff Pairs in an Array	Easy	28.2%	ArrayTwo Pointers
560	Subarray Sum Equals K	Medium	40.2%	ArrayMap
545	Boundary of Binary Tree	Medium	31.7%	Tree
543	Diameter of Binary Tree	Easy	44.4%	Tree
538	Convert BST to Greater Tree	Easy	49.4%	Tree
537	Complex Number Multiplication	Medium	64.0%	MathString
542	01 Matrix	Medium	33.3%	Depth-first SearchBreadth-first Search
536	Construct Binary Tree from String	Medium	42.6%	StringTree
566	Reshape the Matrix	Easy	58.5%	Array
554	Brick Wall	Medium	45.7%	Hash Table
549	Binary Tree Longest Consecutive Sequence II	Medium	41.3%	Tree
547	Friend Circles	Medium	49.2%	Depth-first SearchUnion Find
552	Student Attendance Record II	Hard	31.4%	Dynamic Programming
548	Split Array with Equal Sum	Medium	36.8%	Array
546	Remove Boxes	Hard	34.0%	Dynamic ProgrammingDepth-first Search
553	Optimal Division	Medium	55.1%	MathString
546	Remove Boxes	Hard	34.0%	Dynamic ProgrammingDepth-first Search
561	Array Partition I	Easy	66.8%	Array
572	Subtree of Another Tree	Easy	40.8%	Tree
576	Out of Boundary Paths	Medium	30.9%	Dynamic ProgrammingDepth-first Search
568	Maximum Vacation Days	Hard	39.9%	Dynamic Programming
576	Out of Boundary Paths	Medium	30.9%	Dynamic ProgrammingDepth-first Search
575	Distribute Candies	Easy	58.7%	Hash Table
581	Shortest Unsorted Continuous Subarray	Easy	29.5%	Array
573	Squirrel Simulation	Medium	52.3%	Math
594	Longest Harmonious Subsequence	Easy	41.1%	Hash Table
588	Design In-Memory File System	Hard	34.7%	Design
592	Fraction Addition and Subtraction	Medium	46.4%	Math
593	Valid Square	Medium	40.0%	Math
654	Maximum Binary Tree	Medium	70.2%	Tree
605	Can Place Flowers	Easy	30.0%	Array
599	Minimum Index Sum of Two Lists	Easy	46.3%	Hash Table
600	Non-negative Integers without Consecutive Ones	Hard	30.4%	Dynamic Programming
604	Design Compressed String Iterator	Easy	32.4%	Design
644	Maximum Average Subarray II	Hard	22.1%	ArrayBinary Search
656	Coin Path	Hard	24.5%	Dynamic Programming
638	Shopping Offers	Medium	42.9%	Dynamic ProgrammingDepth-first Search
621	Task Scheduler	Medium	42.1%	ArrayGreedyQueue
642	Design Search Autocomplete System	Hard	30.0%	DesignTrie
652	Find Duplicate Subtrees	Medium	34.9%	Tree
628	Maximum Product of Three Numbers	Easy	45.0%	ArrayMath
637	Average of Levels in Binary Tree	Easy	55.8%	Tree
635	Design Log Storage System	Medium	48.4%	StringDesign
644	Maximum Average Subarray II	Hard	22.1%	ArrayBinary Search
631	Design Excel Sum Formula	Hard	26.6%	Design
629	K Inverse Pairs Array	Hard	26.7%	Dynamic Programming
643	Maximum Average Subarray I	Easy	37.7%	Array
609	Find Duplicate File in System	Medium	52.5%	Hash TableString
624	Maximum Distance in Arrays	Easy	34.1%	ArrayHash Table
611	Valid Triangle Number	Medium	41.7%	Array
617	Merge Two Binary Trees	Easy	67.9%	Tree
634	Find the Derangement of An Array	Medium	33.8%	Math
633	Sum of Square Numbers	Easy	32.2%	Math
628	Maximum Product of Three Numbers	Easy	45.0%	ArrayMath
625	Minimum Factorization	Medium	30.7%	MathRecursion
624	Maximum Distance in Arrays	Easy	34.1%	ArrayHash Table
632	Smallest Range	Hard	42.4%	Hash TableTwo PointersString
623	Add One Row to Tree	Medium	46.6%	Tree
640	Solve the Equation	Medium	39.0%	Math
638	Shopping Offers	Medium	42.9%	Dynamic ProgrammingDepth-first Search
645	Set Mismatch	Easy	40.3%	Hash TableMath
648	Replace Words	Medium	47.7%	Hash TableTrie
650	2 Keys Keyboard	Medium	44.1%	Dynamic Programming
646	Maximum Length of Pair Chain	Medium	47.7%	Dynamic Programming
651	4 Keys Keyboard	Medium	47.9%	MathDynamic ProgrammingGreedy
645	Set Mismatch	Easy	40.3%	Hash TableMath
647	Palindromic Substrings	Medium	55.8%	StringDynamic Programming
655	Print Binary Tree	Medium	50.6%	Tree
651	4 Keys Keyboard	Medium	47.9%	MathDynamic ProgrammingGreedy
632	Smallest Range	Hard	42.4%	Hash TableTwo PointersString
653	Two Sum IV - Input is a BST	Easy	50.7%	Tree
606	Construct String from Binary Tree	Easy	49.8%	StringTree
690	Employee Importance	Easy	55.5%	Hash TableDepth-first SearchBreadth-first Search
660	Remove 9	Hard	47.1%	Math
658	Find K Closest Elements	Medium	35.7%	Binary Search
683	K Empty Slots	Hard	37.2%	ArrayBinary Search Tree
661	Image Smoother	Easy	45.8%	Array
671	Second Minimum Node In a Binary Tree	Easy	41.9%	Tree
679	24 Game	Hard	38.5%	Depth-first Search
670	Maximum Swap	Medium	38.4%	ArrayMath
664	Strange Printer	Hard	31.4%	Dynamic ProgrammingDepth-first Search
664	Strange Printer	Hard	31.4%	Dynamic ProgrammingDepth-first Search
669	Trim a Binary Search Tree	Easy	58.4%	Tree
666	Path Sum IV	Medium	49.4%	Tree
665	Non-decreasing Array	Easy	21.3%	Array
668	Kth Smallest Number in Multiplication Table	Hard	37.0%	Binary Search
667	Beautiful Arrangement II	Medium	51.6%	Array
676	Implement Magic Dictionary	Medium	50.0%	Hash TableTrie
670	Maximum Swap	Medium	38.4%	ArrayMath
674	Longest Continuous Increasing Subsequence	Easy	43.0%	Array
672	Bulb Switcher II	Medium	48.1%	Math
673	Number of Longest Increasing Subsequence	Medium	30.9%	Dynamic Programming
663	Equal Tree Partition	Medium	36.6%	Tree
662	Maximum Width of Binary Tree	Medium	37.7%	Tree
689	Maximum Sum of 3 Non-Overlapping Subarrays	Hard	42.9%	ArrayDynamic Programming
684	Redundant Connection	Medium	35.8%	TreeUnion FindGraph
690	Employee Importance	Easy	55.5%	Hash TableDepth-first SearchBreadth-first Search
689	Maximum Sum of 3 Non-Overlapping Subarrays	Hard	42.9%	ArrayDynamic Programming
685	Redundant Connection II	Hard	28.8%	TreeDepth-first SearchUnion FindGraph
688	Knight Probability in Chessboard	Medium	38.3%	Dynamic Programming
687	Longest Univalue Path	Easy	32.3%	TreeRecursion
685	Redundant Connection II	Hard	28.8%	TreeDepth-first SearchUnion FindGraph
695	Max Area of Island	Easy	53.3%	ArrayDepth-first Search
691	Stickers to Spell Word	Hard	31.7%	Dynamic ProgrammingBacktracking
691	Stickers to Spell Word	Hard	31.7%	Dynamic ProgrammingBacktracking
692	Top K Frequent Words	Medium	41.1%	Hash TableHeapTrie
694	Number of Distinct Islands	Medium	43.5%	Hash TableDepth-first Search
694	Number of Distinct Islands	Medium	43.5%	Hash TableDepth-first Search
695	Max Area of Island	Easy	53.3%	ArrayDepth-first Search
697	Degree of an Array	Easy	48.9%	Array
698	Partition to K Equal Sum Subsets	Medium	34.7%	Dynamic ProgrammingRecursion
711	Number of Distinct Islands II	Hard	26.0%	Hash TableDepth-first Search
711	Number of Distinct Islands II	Hard	26.0%	Hash TableDepth-first Search

Tag:two-pointers

ID	Title	Difficulty	Acceptance	Tags
285	Inorder Successor in BST	Medium	36.2%	Tree
268	Missing Number	Easy	44.3%	ArrayMathBit Manipulation
1	Two Sum	Easy	35.6%	ArrayHash Table
4	Median of Two Sorted Arrays	Hard	22.1%	ArrayBinary SearchDivide and Conquer
3	Longest Substring Without Repeating Characters	Medium	24.4%	Hash TableTwo PointersString
2	Add Two Numbers	Medium	28.0%	Linked ListMath
7	Reverse Integer	Easy	24.5%	Math
8	String to Integer (atoi)	Medium	14.0%	MathString
9	Palindrome Number	Easy	35.5%	Math
10	Regular Expression Matching	Hard	24.2%	StringDynamic ProgrammingBacktracking
4	Median of Two Sorted Arrays	Hard	22.1%	ArrayBinary SearchDivide and Conquer
1	Two Sum	Easy	35.6%	ArrayHash Table
3	Longest Substring Without Repeating Characters	Medium	24.4%	Hash TableTwo PointersString
107	Binary Tree Level Order Traversal II	Easy	40.8%	TreeBreadth-first Search
42	Trapping Rain Water	Hard	37.0%	ArrayTwo PointersStack
45	Jump Game II	Hard	26.2%	ArrayGreedy
48	Rotate Image	Medium	39.5%	Array
53	Maximum Subarray	Easy	39.8%	ArrayDivide and ConquerDynamic Programming
54	Spiral Matrix	Medium	26.4%	Array
55	Jump Game	Medium	29.5%	ArrayGreedy
56	Merge Intervals	Medium	30.7%	ArraySort
57	Insert Interval	Hard	28.1%	ArraySort
59	Spiral Matrix II	Medium	40.1%	Array
62	Unique Paths	Medium	41.7%	ArrayDynamic Programming
63	Unique Paths II	Medium	31.9%	ArrayDynamic Programming
64	Minimum Path Sum	Medium	38.9%	ArrayDynamic Programming
66	Plus One	Easy	38.9%	ArrayMath
73	Set Matrix Zeroes	Medium	36.1%	Array
74	Search a 2D Matrix	Medium	34.9%	ArrayBinary Search
75	Sort Colors	Medium	38.3%	ArrayTwo PointersSort
78	Subsets	Medium	41.8%	ArrayBacktrackingBit Manipulation
79	Word Search	Medium	27.2%	ArrayBacktracking
80	Remove Duplicates from Sorted Array II	Medium	36.3%	ArrayTwo Pointers
81	Search in Rotated Sorted Array II	Medium	32.7%	ArrayBinary Search
84	Largest Rectangle in Histogram	Hard	27.0%	ArrayStack
85	Maximal Rectangle	Hard	28.5%	ArrayHash TableDynamic ProgrammingStack
88	Merge Sorted Array	Easy	32.1%	ArrayTwo Pointers
90	Subsets II	Medium	36.9%	ArrayBacktracking
105	Construct Binary Tree from Preorder and Inorder Traversal	Medium	32.6%	ArrayTreeDepth-first Search
106	Construct Binary Tree from Inorder and Postorder Traversal	Medium	32.4%	ArrayTreeDepth-first Search
41	First Missing Positive	Hard	25.6%	Array
40	Combination Sum II	Medium	34.4%	ArrayBacktracking
39	Combination Sum	Medium	39.5%	ArrayBacktracking
35	Search Insert Position	Easy	39.8%	ArrayBinary Search
34	Search for a Range	Medium	31.4%	ArrayBinary Search
33	Search in Rotated Sorted Array	Medium	32.1%	ArrayBinary Search
31	Next Permutation	Medium	28.8%	Array
27	Remove Element	Easy	39.6%	ArrayTwo Pointers
26	Remove Duplicates from Sorted Array	Easy	35.4%	ArrayTwo Pointers
18	4Sum	Medium	27.0%	ArrayHash TableTwo Pointers
16	3Sum Closest	Medium	31.3%	ArrayTwo Pointers
15	3Sum	Medium	21.8%	ArrayTwo Pointers
11	Container With Most Water	Medium	36.8%	ArrayTwo Pointers
98	Validate Binary Search Tree	Medium	23.6%	TreeDepth-first Search
99	Recover Binary Search Tree	Hard	30.2%	TreeDepth-first Search
100	Same Tree	Easy	46.8%	TreeDepth-first Search
101	Symmetric Tree	Easy	39.2%	TreeDepth-first SearchBreadth-first Search
104	Maximum Depth of Binary Tree	Easy	53.1%	TreeDepth-first Search
105	Construct Binary Tree from Preorder and Inorder Traversal	Medium	32.6%	ArrayTreeDepth-first Search
106	Construct Binary Tree from Inorder and Postorder Traversal	Medium	32.4%	ArrayTreeDepth-first Search
94	Binary Tree Inorder Traversal	Medium	47.4%	Hash TableStackTree
85	Maximal Rectangle	Hard	28.5%	ArrayHash TableDynamic ProgrammingStack
76	Minimum Window Substring	Hard	25.9%	Hash TableTwo PointersString
49	Group Anagrams	Medium	35.9%	Hash TableString
37	Sudoku Solver	Hard	30.8%	Hash TableBacktracking
36	Valid Sudoku	Medium	36.3%	Hash Table
30	Substring with Concatenation of All Words	Hard	22.0%	Hash TableTwo PointersString
18	4Sum	Medium	27.0%	ArrayHash TableTwo Pointers
32	Longest Valid Parentheses	Hard	23.1%	StringDynamic Programming
44	Wildcard Matching	Hard	20.4%	StringDynamic ProgrammingBacktrackingGreedy
53	Maximum Subarray	Easy	39.8%	ArrayDivide and ConquerDynamic Programming
62	Unique Paths	Medium	41.7%	ArrayDynamic Programming
63	Unique Paths II	Medium	31.9%	ArrayDynamic Programming
64	Minimum Path Sum	Medium	38.9%	ArrayDynamic Programming
70	Climbing Stairs	Easy	40.3%	Dynamic Programming
108	Convert Sorted Array to Binary Search Tree	Easy	42.5%	TreeDepth-first Search
109	Convert Sorted List to Binary Search Tree	Medium	34.4%	Linked ListDepth-first Search
110	Balanced Binary Tree	Easy	37.8%	TreeDepth-first Search
111	Minimum Depth of Binary Tree	Easy	33.3%	TreeDepth-first SearchBreadth-first Search
112	Path Sum	Easy	34.2%	TreeDepth-first Search
113	Path Sum II	Medium	34.3%	TreeDepth-first Search
114	Flatten Binary Tree to Linked List	Medium	35.5%	TreeDepth-first Search
116	Populating Next Right Pointers in Each Node	Medium	36.9%	TreeDepth-first Search
11	Container With Most Water	Medium	36.8%	ArrayTwo Pointers
15	3Sum	Medium	21.8%	ArrayTwo Pointers
16	3Sum Closest	Medium	31.3%	ArrayTwo Pointers
18	4Sum	Medium	27.0%	ArrayHash TableTwo Pointers
19	Remove Nth Node From End of List	Medium	33.8%	Linked ListTwo Pointers
26	Remove Duplicates from Sorted Array	Easy	35.4%	ArrayTwo Pointers
27	Remove Element	Easy	39.6%	ArrayTwo Pointers
28	Implement strStr()	Easy	28.4%	Two PointersString
30	Substring with Concatenation of All Words	Hard	22.0%	Hash TableTwo PointersString
42	Trapping Rain Water	Hard	37.0%	ArrayTwo PointersStack
61	Rotate List	Medium	24.3%	Linked ListTwo Pointers
75	Sort Colors	Medium	38.3%	ArrayTwo PointersSort
76	Minimum Window Substring	Hard	25.9%	Hash TableTwo PointersString
80	Remove Duplicates from Sorted Array II	Medium	36.3%	ArrayTwo Pointers
86	Partition List	Medium	33.0%	Linked ListTwo Pointers
88	Merge Sorted Array	Easy	32.1%	ArrayTwo Pointers
94	Binary Tree Inorder Traversal	Medium	47.4%	Hash TableStackTree
95	Unique Binary Search Trees II	Medium	31.7%	Dynamic ProgrammingTree
96	Unique Binary Search Trees	Medium	41.3%	Dynamic ProgrammingTree
72	Edit Distance	Hard	32.0%	StringDynamic Programming
85	Maximal Rectangle	Hard	28.5%	ArrayHash TableDynamic ProgrammingStack
87	Scramble String	Hard	29.4%	StringDynamic Programming
98	Validate Binary Search Tree	Medium	23.6%	TreeDepth-first Search
99	Recover Binary Search Tree	Hard	30.2%	TreeDepth-first Search
100	Same Tree	Easy	46.8%	TreeDepth-first Search
101	Symmetric Tree	Easy	39.2%	TreeDepth-first SearchBreadth-first Search
102	Binary Tree Level Order Traversal	Medium	40.6%	TreeBreadth-first Search
103	Binary Tree Zigzag Level Order Traversal	Medium	35.2%	StackTreeBreadth-first Search
104	[Maximum Depth of Binary Tree](https://leetc

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