JS - Leap Year, Circular Linked List and Tree (not binary)

js/dius00_dataStructure_Tree.js

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+ // Javascript ES6 syntax code sample for Tree (non-binary) data structure
+
+/* 
+* Creates the Tree
+* if a value is given to the constructor
+* the element will be initialized as an instance of Tree
+*/
+class Tree {
+  constructor(value) {
+    if(value !== undefined){
+      this.value = value;
+      this.children = [];
+    }
+  }
+
+/* 
+* Method to add a new child to the Tree
+*/
+  addChild(value) {
+    const newTree = new Tree(value); // Generates a new Tree element
+    this.children.push(newTree);     // Adds the newTree (child) to the children Array
+    return newTree;                  // Returns the new Tree
+  }
+
+/* 
+* Method to check if a value exists in the tree
+*/
+  contains(value) {
+    // initializes the result as false
+    let result = false;           
+
+    /* 
+    * declare a searchValue function that travels recursivly
+    * through the Tree and his Childre  
+    */  
+     function searchValue(tree) {    
+      // if the current Tree value is equal to the one we are looking for
+      // change the result to true
+      if (tree.value === value) result = true;
+      // if the Tree has children
+      if (tree.children !== []) {
+        // for each of them call an instance of the searchValue function
+        for (const child of tree.children) searchValue(child);
+      }
+    }
+    // call the searchValue function on or parent Tree
+    searchValue(this);
+
+    // returns the result
+    return result;
+  }
+
+  /* 
+  * Method to remove and 
+  * return all the (children) Trees if it they a certain value
+  */
+  remove(value) {
+    // initializes the array that will contain all the removed trees
+    const removedTrees = [];
+    /* 
+    * declare a removeValue function that travels recursivly
+    * through the Tree and his Children, if it finds a child 
+    * with the matching value, it pushed it to removedTrees  
+    * and removes it from the list of children
+    */
+    function removeValue(tree) {
+      // if a tree has children
+      if (tree.children !== []) {
+        // iterate through the children
+        for (const child of tree.children) {
+          // if the child(Tree) has a matching value
+          if (child.value === value) {
+            // pushes the child(Tree) into removedTrees
+            removedTrees.push(child);
+            // removes the child(Tree) from the parent children array
+            tree.children.splice(tree.children.indexOf(removedValue), 1);
+            } 
+          }
+          // afterwards iterates through the remaining children
+          // by calling removeValue recursivly
+          for (const child of tree.children) removeValue(child);
+        }
+      }
+    // calls removeValue
+    removeValue(this);
+    // returns the removed value
+    return removedValue;
+  }
+}

js/dius00_dataStructure_circularLinkedList.js

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+// Javascript ES6 syntax code sample for Circular Linked List
+
+
+/* 
+* Creates the Linked List
+* if a value is given to the constructor
+* the element will be initialized as a Node (below)
+*/
+class CircularLinkedList {
+  constructor(value){
+      if(value !== undefined){
+      this.sentinel = new Node(value); // a "sentinel" node has to be set in order control Read/Write operation
+      }
+  }
+/* 
+* Method to add a new Node to the list
+*/
+  addNode(value){
+      const newNode = new Node(value);  // Generates a new Node element
+      if(!this.sentinel) {              // if there is no head make the new Node the head of the list
+          this.sentinel = newNode;
+          this.sentinel.next = newNode;
+          this.sentinel.prev = newNode;
+          return;
+      } else {                          // if there is a head, link the new Node to the tail of the list
+      newNode.next = this.sentinel;
+      newNode.prev = this.sentinel.prev.prev;
+      this.sentinel.prev.next = newNode;
+      this.sentinel.prev = newNode;
+    }
+  }
+
+/* 
+* Method to find a specific Node in the list
+*/
+
+ findNode(value) {
+   if(this.sentinel){
+      let iterator = this.sentinel;
+      while(true) {
+        if (iterator.value === value) return iterator;
+        iterator = iterator.next;
+        if(iterator === this.sentinel) break;
+      }
+    }
+      return null;
+    }
+}
+
+class Node {
+  constructor(value){
+      this.value = value;
+      this.next = null;
+      this.prev = null;
+  }
+}

js/dius00_leapYear.js

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+// A year is a Leap Year
+
+// on every year that is evenly divisible by 4
+// except every year that is evenly divisible by 100
+// unless the year is also evenly divisible by 400
+
+
+function isLeap (num) {
+  // if a number ends with X00 it is divible by 100
+  if(num.toString().substring(2,) == '00'){ 
+    // if a number is divisible by 100 and 400 it is a leap year and return true
+    if(num % 400 == 0) return true;
+    // if a number is divisible by 100 and not by 400 it is not a leap year and return false
+    else return false;
+  }
+  // if a number is not divisible by 100
+  else{
+    // if it is divisible by 4 it is a leap year and return false
+    if(num%4 == 0) return true;
+    // if it is not divisible by 4 it is not a leap year
+    else return false;
+  }
+};
+
+// examples
+
+console.log(isLeap(2100)) // ==> false
+
+console.log(isLeap(2000)) // ==> true
+
+console.log(isLeap(2020)) // ==> true
+
+console.log(isLeap(1975)) // ==> false
+
+console.log(isLeap(312))  // ==> true