Merge pull request codemistic#558 from KryptonANSHU/Javascript-DSA

Added New Folder (Javascript DSA) | Added Linked list code with JS

Author: gantavyamalviya

DSA Javascript/Stack_Using_Singly_Linked_List.js

@@ -0,0 +1,83 @@
+//Stack using linkedlist
+function stackUsingLL(){
+ //Node 
+ let Node = function(elm){
+ this.element = elm;
+ this.next = null;
+ }
+ 
+ //To keep track of the size 
+ let length = 0;
+ 
+ //To keep track of the list
+ let head = null;
+ 
+ //Push data in the stack
+ this.push = function(elm){
+ //Create a new node
+ let node = new Node(elm),
+ current;
+ 
+ //Add the new node at the top
+ current = head;
+ node.next = current;
+ head = node;
+ 
+ length++;
+ }
+ 
+ //Pop the item from the stack
+ this.pop = function(){
+ let current = head;
+ 
+ //If there is item then remove it 
+ //and make the next element as the first
+ if(current){
+ let elm = current.element;
+ current = current.next;
+ head = current;
+ length--;
+ return elm;
+ }
+ 
+ return null; 
+ }
+ 
+ //Return the first element in the stack
+ this.peek = function(){ 
+ if(head){ 
+ return head.element;
+ }
+
+ return null;
+ }
+ 
+ //Convert the stack to an array
+ this.toArray = function(){
+ let arr = [];
+ let current = head;
+ while(current){
+ arr.push(current.element);
+ current = current.next;
+ }
+ 
+ return arr;
+ }
+ 
+ //Check if stack is empty
+ this.isEmpty = function(){
+ return length === 0;
+ }
+ 
+ //Return the size of the stack
+ this.size = function(){
+ return length;
+ }
+ 
+ //Clear the stack
+ this.clear = function(){
+ head = null;
+ length = 0;
+ }
+ 
+}

DSA Javascript/linked_list.js

@@ -0,0 +1,230 @@
+class Node {
+ // constructor
+ constructor(element) {
+ this.element = element;
+ this.next = null
+ }
+}
+// linkedlist class
+class LinkedList {
+ constructor() {
+ this.head = null;
+ this.size = 0;
+ }
+ 
+ // adds an element at the end
+ // of list
+ add(element) {
+ // creates a new node
+ var node = new Node(element);
+ 
+ // to store current node
+ var current;
+ 
+ // if list is Empty add the
+ // element and make it head
+ if (this.head == null)
+ this.head = node;
+ else {
+ current = this.head;
+ 
+ // iterate to the end of the
+ // list
+ while (current.next) {
+ current = current.next;
+ }
+ 
+ // add node
+ current.next = node;
+ }
+ this.size++;
+ }
+ 
+ // insert element at the position index
+ // of the list
+ insertAt(element, index) {
+ if (index < 0 || index > this.size)
+ return console.log("Please enter a valid index.");
+ else {
+ // creates a new node
+ var node = new Node(element);
+ var curr, prev;
+ 
+ curr = this.head;
+ 
+ // add the element to the
+ // first index
+ if (index == 0) {
+ node.next = this.head;
+ this.head = node;
+ } else {
+ curr = this.head;
+ var it = 0;
+ 
+ // iterate over the list to find
+ // the position to insert
+ while (it < index) {
+ it++;
+ prev = curr;
+ curr = curr.next;
+ }
+ 
+ // adding an element
+ node.next = curr;
+ prev.next = node;
+ }
+ this.size++;
+ }
+ }
+ 
+ // removes an element from the
+ // specified location
+ removeFrom(index) {
+ if (index < 0 || index >= this.size)
+ return console.log("Please Enter a valid index");
+ else {
+ var curr, prev, it = 0;
+ curr = this.head;
+ prev = curr;
+ 
+ // deleting first element
+ if (index === 0) {
+ this.head = curr.next;
+ } else {
+ // iterate over the list to the
+ // position to removce an element
+ while (it < index) {
+ it++;
+ prev = curr;
+ curr = curr.next;
+ }
+ 
+ // remove the element
+ prev.next = curr.next;
+ }
+ this.size--;
+ 
+ // return the remove element
+ return curr.element;
+ }
+ }
+ 
+ // removes a given element from the
+ // list
+ removeElement(element) {
+ var current = this.head;
+ var prev = null;
+ 
+ // iterate over the list
+ while (current != null) {
+ // comparing element with current
+ // element if found then remove the
+ // and return true
+ if (current.element === element) {
+ if (prev == null) {
+ this.head = current.next;
+ } else {
+ prev.next = current.next;
+ }
+ this.size--;
+ return current.element;
+ }
+ prev = current;
+ current = current.next;
+ }
+ return -1;
+ }
+ 
+ 
+ // finds the index of element
+ indexOf(element) {
+ var count = 0;
+ var current = this.head;
+ 
+ // iterate over the list
+ while (current != null) {
+ // compare each element of the list
+ // with given element
+ if (current.element === element)
+ return count;
+ count++;
+ current = current.next;
+ }
+ 
+ // not found
+ return -1;
+ }
+ 
+ // checks the list for empty
+ isEmpty() {
+ return this.size == 0;
+ }
+ 
+ // gives the size of the list
+ size_of_list() {
+ console.log(this.size);
+ }
+ 
+ 
+ // prints the list items
+ printList() {
+ var curr = this.head;
+ var str = "";
+ while (curr) {
+ str += curr.element + " ";
+ curr = curr.next;
+ }
+ console.log(str);
+ }
+ 
+}
+ 
+// creating an object for the
+// Linkedlist class
+var ll = new LinkedList();
+ 
+// testing isEmpty on an empty list
+// returns true
+console.log(ll.isEmpty());
+ 
+// adding element to the list
+ll.add(10);
+ 
+// prints 10
+ll.printList();
+ 
+// returns 1
+console.log(ll.size_of_list());
+ 
+// adding more elements to the list
+ll.add(20);
+ll.add(30);
+ll.add(40);
+ll.add(50);
+ 
+// returns 10 20 30 40 50
+ll.printList();
+ 
+// prints 50 from the list
+console.log("is element removed ?" + ll.removeElement(50));
+ 
+// prints 10 20 30 40
+ll.printList();
+ 
+// returns 3
+console.log("Index of 40 " + ll.indexOf(40));
+ 
+// insert 60 at second position
+// ll contains 10 20 60 30 40
+ll.insertAt(60, 2);
+ 
+ll.printList();
+ 
+// returns false
+console.log("is List Empty ? " + ll.isEmpty());
+ 
+// remove 3rd element from the list
+console.log(ll.removeFrom(3));
+ 
+// prints 10 20 60 40
+ll.printList();