Create singlyLL.js

01. DataStructures/01. Linked List/1. Singly-Linked-List/Basic Operations/singlyLL.js

@@ -0,0 +1,138 @@
+//create a linked list class that add data at first position, 
+//at last position, at given position, get data from last, get data from first, and get data from the give position
+
+class node {
+ constructor(data, next = null) {
+ this.data = data;
+ this.next = next; 
+ }
+}
+
+
+ class linkedList {
+ constructor() {
+ this.head = null;
+ this.size = 0;
+ }
+
+ // insert the elment at the first positoin 
+ insertFirst(data) {
+ this.head = new node(data, this.head);
+ this.size++;
+ }
+ insertLast(data) {
+ let currunt = this.head;
+
+ while(currunt.next) {
+ currunt = currunt.next;
+ }
+ currunt.next = new node(data);
+ this.size++;
+ }
+ // print all the element in linked list from the last element
+ printDataFromTheEnd() {
+ let linkedStr = 'null';
+ let currunt = this.head
+ while(currunt) {
+ linkedStr += "->" + currunt.data; 
+ currunt = currunt.next;
+ }
+ return linkedStr;
+ }
+ // print data from the first element
+ printDataFromTheStart() {
+ let currunt = this.head;
+ let reversL = this.reverseLink(currunt);
+ let linkedStr = '';
+ while(reversL) {
+ linkedStr += reversL.data + "->" ; 
+ reversL = reversL.next;
+ }
+ return linkedStr + 'null';
+ }
+ // insert data at specific position. it is zero based index.
+ insertAt(data, index) {
+ if(index < 0 || index > this.size) {
+ return 'index must be between linked list size';
+ }
+
+ let currunt = this.head;
+ index = this.size - index;
+ console.log(index);
+ while(index > 0) {
+ currunt = currunt.next;
+ index--;
+ }
+ currunt.next = new node(data, currunt.next);
+ this.size++;
+ return this.printDataFromTheStart();
+ }
+ getAt(index) {
+ let currunt = this.head;
+ if(index < 0 || index > this.size) {
+ return 'index must be between linked list size';
+ }
+ let reverseL = this.reverseLink(currunt)
+ while(index > 1) {
+ reverseL = reverseL.next;
+ index--;
+ }
+ return reverseL.data;
+ }
+ // remove at 
+ removeAt(index) {
+ if(index < 0 || index > this.size) {
+ return 'index must be between linked list size';
+ }
+
+ let currunt = this.head;
+ index = this.size - index;
+ while(index > 1) {
+ currunt = currunt.next;
+ index--;
+ }
+ let temp = currunt.next;
+ currunt.next = currunt.next.next;
+ temp = null;
+ this.size--;
+ }
+ // reverse the link list 
+ reverseLink(head) {
+ let temp = null;
+ while(head) {
+ let tempHead = head.next;
+ head.next = temp;
+ temp = head;
+ head = tempHead; 
+ }
+ return temp;
+ }
+
+ // delete the list 
+ deleteList() {
+ while(this.head) {
+ // 1->2->3->4->5->6
+ let temp = this.head;
+ this.head = this.head.next;
+ temp = null;
+ }
+ return this.head;
+ }
+}
+
+const ll = new linkedList();
+
+ll.insertFirst(100);
+ll.insertFirst(200);
+ll.insertFirst(300);
+ll.insertFirst(400);
+ll.insertFirst(500);
+ll.insertFirst(600);
+ll.insertFirst(700);
+// ll.removeAt(3);
+console.log(ll.insertAt(555, 5));
+
+// console.log(ll.printDataFromTheStart());
+// console.log(ll.removeAt(2));
+// console.log(ll.printDataFromTheEnd());
+