LeetCode Solutions

LeetCode problems and solutions

#	Title	Solution	Difficulty
1	Two Sum	C#	Easy
2	Add Two Numbers	C#	Medium
3	Longest Substring Without Repeating Characters	C#	Medium
4	Median of Two Sorted Arrays	C#	Hard
4	Median of Two Sorted Arrays	Java	Hard
5	Longest Palindromic Substring	C#	Medium
6	Zigzag Conversion	C#	Medium
7	Reverse Integer	C#	Medium
8	String to Integer (atoi)	C#	Medium
9	Palindrome Number	C#	Easy
10	Regular Expression Matching	C#	Hard
11	Container With Most Water	C#	Medium
12	Integer to Roman	C#	Medium
13	Roman to Integer	C#	Easy
14	Longest Common Prefix	C#	Easy
15	3Sum	C#	Medium
16	3Sum Closest	C#	Medium
17	Letter Combinations of a Phone Number	C#	Medium
18	4Sum	C#	Medium
19	Remove Nth Node From End of List	C#	Medium
20	Valid Parentheses	C#	Easy
21	Merge Two Sorted Lists	C#	Easy
22	Generate Parentheses	C#	Medium
23	Merge k Sorted Lists	C#	Hard
24	Swap Nodes in Pairs	C#	Medium
25	Reverse Nodes in k-Group	C#	Hard
26	Remove Duplicates from Sorted Array	C#	Easy
27	Remove Element	C#	Easy
28	Find the Index of the First Occurrence in a String	C#	Easy
29	Divide Two Integers	C#	Medium
30	Substring with Concatenation of All Words	C#	Hard
31	Next Permutation	C#	Medium
32	Longest Valid Parentheses	C#	Hard
33	Search in Rotated Sorted Array	C#	Medium
34	Find First and Last Position of Element in Sorted Array	C#	Medium
35	Search Insert Position	C#	Easy
36	Valid Sudoku	C#	Medium
37	Sudoku Solver	C#	Hard
38	Count and Say	C#	Easy
39	Combination Sum	C#	Medium
40	Combination Sum II	C#	Medium
41	First Missing Positive	C#	Hard
42	Trapping Rain Water	C#	Hard
43	Multiply Strings	C#	Medium
44	Wildcard Matching	C#	Hard
45	Jump Game II	C#	Medium
46	Permutations	C#	Medium
47	Permutations II	C#	Medium
48	Rotate Image	C#	Medium
49	Group Anagrams	C#	Medium
50	Pow(x, n)	C#	Medium
51	N-Queens	C#	Hard
52	N-Queens II	C#	Hard
53	Maximum Subarray	C#	Easy
54	Spiral Matrix	C#	Medium
55	Jump Game	C#	Medium
56	Merge Intervals	C#	Medium
57	Insert Interval	C#	Medium
58	Length of Last Word	C#	Easy
59	Spiral Matrix II	C#	Medium
60	Permutation Sequence	C#	Hard
61	Rotate List	C#	Medium
62	Unique Paths	C#	Medium
63	Unique Paths II	C#	Medium
64	Minimum Path Sum	C#	Medium
65	Valid Number	C#	Hard
66	Plus One	C#	Easy
67	Add Binary	C#	Easy
68	Text Justification	C#	Hard
69	Sqrt(x)	C#	Easy
70	Climbing Stairs	Java	Easy
71	Simplify Path	C#	Medium
72	Edit Distance	C#	Medium
73	Set Matrix Zeroes	C#	Medium
74	Search a 2D Matrix	C#	Medium
75	Sort Colors	C#	Medium
76	Minimum Window Substring	C#	Hard
77	Combinations	C#	Medium
78	Subsets	C#	Medium
79	Word Search	C#	Medium
80	Remove Duplicates from Sorted Array II	C#	Medium
81	Search in Rotated Sorted Array II	C#	Medium
82	Remove Duplicates from Sorted List II	C#	Medium
83	Remove Duplicates from Sorted List	Java	Easy
84	Largest Rectangle in Histogram	C#	Hard
85	Maximal Rectangle	C#	Hard
86	Partition List	C#	Medium
87	Scramble String	C#	Hard
88	Merge Sorted Array	Java	Easy
88	Merge Sorted Array	C#	Easy
89	Gray Code	C#	Medium
90	Subsets II	C#	Medium
91	Decode Ways	C#	Medium
92	Reverse Linked List II	C#	Medium
93	Restore IP Addresses	C#	Medium
94	Binary Tree Inorder Traversal	Java	Easy
95	Unique Binary Search Trees II	C#	Medium
96	Unique Binary Search Trees	C#	Medium
97	Interleaving String	C#	Medium
98	Validate Binary Search Tree	C#	Medium
99	Recover Binary Search Tree	C#	Medium
100	Same Tree	Java	Easy
101	Symmetric Tree	Java	Easy
102	Binary Tree Level Order Traversal	C#	Medium
103	Binary Tree Zigzag Level Order Traversal	C#	Medium
104	Maximum Depth of Binary Tree	Java	Easy
105	Construct Binary Tree from Preorder and Inorder Traversal	C#	Medium
106	Construct Binary Tree from Inorder and Postorder Traversal	C#	Medium
107	Binary Tree Level Order Traversal II	C#	Medium
108	Convert Sorted Array to Binary Search Tree	Java	Easy
109	Convert Sorted List to Binary Search Tree	C#	Medium
110	Balanced Binary Tree	C#	Easy
111	Minimum Depth of Binary Tree	C#	Easy
112	Path Sum	C#	Easy
113	Path Sum II	C#	Medium
114	Flatten Binary Tree to Linked List	C#	Medium
115	Distinct Subsequences	C#	Hard
116	Populating Next Right Pointers in Each Node	C#	Medium
117	Populating Next Right Pointers in Each Node II	C#	Medium
118	Pascal's Triangle	C#	Easy
119	Pascal's Triangle II	C#	Easy
120	Triangle	C#	Medium
121	Best Time to Buy and Sell Stock	C#	Easy
122	Best Time to Buy and Sell Stock II	C#	Medium
123	Best Time to Buy and Sell Stock III	C#	Hard
125	Valid Palindrome	C#	Easy
127	Word Ladder	C#	Hard
128	Longest Consecutive Sequence	C#	Medium
129	Sum Root to Leaf Numbers	C#	Medium
130	Surrounded Regions	C#	Medium
131	Palindrome Partitioning	C#	Medium
132	Palindrome Partitioning II	C#	Hard
133	Clone Graph	C#	Medium
134	Gas Station	C#	Medium
135	Candy	C#	Hard
136	Single Number	C#	Easy
137	Single Number II	C#	Medium
138	Copy List with Random Pointer	C#	Medium
139	Word Break	C#	Medium
140	Word Break II	C#	Hard
141	Linked List Cycle	C#	Easy
142	Linked List Cycle II	C#	Medium
143	Reorder List	C#	Medium
144	Binary Tree Preorder Traversal	C#	Easy
145	Binary Tree Postorder Traversal	C#	Easy
146	LRU Cache	C#	Medium
147	Insertion Sort List	C#	Medium
148	Sort List	C#	Medium
149	Max Points on a Line	C#	Hard
150	Evaluate Reverse Polish Notation	C#	Medium
151	Reverse Words in a String	C#	Medium
152	Maximum Product Subarray	C#	Medium
153	Find Minimum in Rotated Sorted Array	C#	Medium
154	Find Minimum in Rotated Sorted Array II	C#	Hard
155	Min Stack	C#	Medium
160	Intersection of Two Linked Lists	C#	Easy
162	Find Peak Element	C#	Medium
164	Maximum Gap	C#	Medium
165	Compare Version Numbers	C#	Medium
166	Fraction to Recurring Decimal	C#	Medium
167	Two Sum II - Input Array Is Sorted	C#	Medium
168	Excel Sheet Column Title	C#	Easy
169	Majority Element	C#	Easy
171	Excel Sheet Column Number	C#	Easy
172	Factorial Trailing Zeroes	C#	Medium
173	Binary Search Tree Iterator	C#	Medium
174	Dungeon Game	C#	Hard
175	Combine Two Tables	SQL	Easy
176	Second Highest Salary	SQL	Medium
177	Nth Highest Salary	SQL	Medium
178	Rank Scores	SQL	Medium
179	Largest Number	C#	Medium
181	Employees Earning More Than Their Managers	SQL	Easy
187	Repeated DNA Sequences	C#	Medium
188	Best Time to Buy and Sell Stock IV	C#	Hard
189	Rotate Array	C#	Medium
190	Reverse Bits	C#	Easy
191	Number of 1 Bits	C#	Easy
192	Word Frequency	Shell	Medium
193	Valid Phone Numbers	Shell	Easy
194	Transpose File	Shell	Medium
195	Tenth Line	Shell	Easy
196	Delete Duplicate Emails	SQL	Easy
197	Rising Temperature	SQL	Easy
198	House Robber	C#	Medium
199	Binary Tree Right Side View	C#	Medium
200	Number of Islands	C#	Medium
201	Bitwise AND of Numbers Range	C#	Medium
202	Happy Number	C#	Easy
203	Remove Linked List Elements	C#	Easy
204	Count Primes	C#	Easy
205	Isomorphic Strings	C#	Easy
206	Reverse Linked List	C#	Easy
207	Course Schedule	C#	Medium
208	Implement Trie (Prefix Tree)	C#	Medium
209	Minimum Size Subarray Sum	C#	Medium
210	Course Schedule II	C#	Medium
211	Design Add and Search Words Data Structure	C#	Medium
212	Word Search II	C#	Hard
213	House Robber II	C#	Medium
214	Shortest Palindrome	C#	Hard
215	Kth Largest Element in an Array	C#	Medium
216	Combination Sum III	C#	Medium
217	Contains Duplicate	C#	Easy
218	The Skyline Problem	C#	Hard
219	Contains Duplicate II	C#	Medium
220	Contains Duplicate III	C#	Hard
221	Maximal Square	C#	Medium
222	Count Complete Tree Nodes	C#	Medium
223	Rectangle Area	C#	Medium
224	Basic Calculator	C#	Hard
225	Implement Stack using Queues	C#	Easy
226	Invert Binary Tree	C#	Easy
227	Basic Calculator II	C#	Medium
228	Summary Ranges	C#	Easy
229	Majority Element II	C#	Medium
230	Kth Smallest Element in a BST	C#	Medium
231	Power of Two	C#	Easy
232	Implement Queue using Stacks	C#	Easy
233	Number of Digit One	C#	Hard
234	Palindrome Linked List	C#	Easy
235	Lowest Common Ancestor of a Binary Search Tree	C#	Easy
236	Lowest Common Ancestor of a Binary Tree	C#	Medium
237	Delete Node in a Linked List	C#	Easy
238	Product of Array Except Self	C#	Medium
239	Sliding Window Maximum	C#	Hard
240	Search a 2D Matrix II	C#	Medium
241	Different Ways to Add Parentheses	C#	Medium
242	Valid Anagram	C#	Easy
257	Binary Tree Paths	C#	Easy
258	Add Digits	C#	Easy
260	Single Number III	C#	Medium
263	Ugly Number	C#	Easy
264	Ugly Number II	C#	Medium
268	Missing Number	C#	Easy
273	Integer to English Words	C#	Hard
274	H-Index	C#	Medium
275	H-Index II	C#	Medium
278	First Bad Version	C#	Easy
283	Move Zeroes	C#	Easy
289	Game of Life	C#	Medium
290	Word Pattern	C#	Easy
316	Remove Duplicate Letters	C#	Medium
334	Increasing Triplet Subsequence	C#	Medium
338	Counting Bits	C#	Medium
345	Reverse Vowels of a String	C#	Easy
380	Insert Delete GetRandom O(1)	C#	Medium
383	Ransom Note	C#	Easy
392	Is Subsequence	C#	Easy
452	Minimum Number of Arrows to Burst Balloons	C#	Medium
605	Can Place Flowers	C#	Easy
785	Is Graph Bipartite?	C#	Medium
887	Super Egg Drop	C#	Hard
997	Find the Town Judge	C#	Easy
1071	Greatest Common Divisor of Strings	C#	Easy
1081	Smallest Subsequence of Distinct Characters	C#	Medium
1095	Find in Mountain Array	C#	Hard
1431	Kids With the Greatest Number of Candies	C#	Easy
1433	Check If a String Can Break Another String	C#	Medium
1768	Merge Strings Alternately	C#	Easy
1971	Find if Path Exists in Graph	C#	Easy
2620	Counter	TypeScript	Easy
2622	Cache With Time Limit	TypeScript	Medium
2621	Sleep	TypeScript	Easy
2623	Memoize	TypeScript	Medium
2625	Flatten Deeply Nested Array	TypeScript	Medium
2626	Array Reduce Transformation	TypeScript	Easy
2627	Debounce	TypeScript	Medium
2629	Function Composition	TypeScript	Easy
2631	Group By	TypeScript	Medium
2634	Filter Elements from Array	TypeScript	Easy
2635	Apply Transform Over Each Element in Array	TypeScript	Easy
2637	Promise Time Limit	TypeScript	Medium
2665	Counter II	TypeScript	Easy
2666	Allow One Function Call	TypeScript	Easy
2667	Create Hello World Function	TypeScript	Easy
2677	Array Prototype Last	TypeScript	Easy
2694	Event Emitter	TypeScript	Medium
2695	Array Wrapper	TypeScript	Easy
2703	Return Length of Arguments Passed	TypeScript	Easy
2704	To Be Or Not To Be	TypeScript	Easy
2705	Compact Object	TypeScript	Medium
2715	Timeout Cancellation	TypeScript	Easy
2721	Execute Asynchronous Functions in Parallel	TypeScript	Medium
2722	Join Two Arrays by ID	TypeScript	Medium
2723	Add Two Promises	TypeScript	Easy
2724	Sort By	TypeScript	Easy
2725	Interval Cancellation	TypeScript	Easy
2726	Calculator with Method Chaining	TypeScript	Easy
2727	Is Object Empty	TypeScript	Easy