Approaching Single and Double Linked Lists Using Javascript With All Operations:- Last Stop Solution

class Node { constructor(value) { this.value = value; this.next = null; } } class SingleLinkedList { constructor(value) { this.head = this.tail = new Node(value); this.size = 1; } append(value) { const newNode = new Node(value); this.tail.next = newNode; this.tail = newNode; this.size++; } prepend(value) { const newNode = new Node(value); newNode.next = this.head; this.head = newNode; this.size++; } insertInMiddle(value) { const newNode = new Node(value); let currentHead = this.head; const pos = Math.floor(this.size/2); let counter = 0 while(currentHead) { if (++counter == pos){ this.size++; const temp = currentHead.next; currentHead.next = newNode; newNode.next = temp; break; } currentHead = currentHead.next; } } traversal() { let currentNode = this.head; while (currentNode) { console.log(currentNode.value); currentNode = currentNode.next; } } deleteAtEnd() { let currentNode = this.head; while(currentNode) { if (currentNode.next.next === null) { currentNode.next = null; this.tail = currentNode; this.size--; } currentNode = currentNode.next; } } deleteAtMiddle() { let currentNode = this.head; const pos = Math.floor(this.size/2); let counter = 0; let previousCounter = null; while (currentNode) { if (counter++ === pos) { previousCounter.next = currentNode.next; this.size--; } previousCounter = currentNode; currentNode = currentNode.next; } } reverse() { let prevNode = null; let nextNode = null; let currentNode = this.head; while (currentNode) { nextNode = currentNode.next; currentNode.next = prevNode; if (prevNode === null) { this.tail = currentNode; } prevNode = currentNode; currentNode = nextNode; } this.head = prevNode; } } const test = new SingleLinkedList(3); test.append(5); test.append(9); test.prepend(13); test.prepend(20) test.insertInMiddle(100); console.log('Head ---> ', test.head); console.log('Tail. -> ', test.tail); console.log('-------------------'); test.traversal(); console.log('----------------After delete at End----------'); test.deleteAtEnd(); test.traversal(); console.log('----------------After delete at Middle----------'); test.deleteAtMiddle(); test.traversal(); console.log('----------------After Reverse Linked List----------'); test.reverse(); test.traversal(); console.log('Head ---> ', test.head); console.log('Tail. -> ', test.tail); /* Head ---> Node { value: 20, next: Node { value: 13, next: Node { value: 100, next: [Node] } } } Tail. -> Node { value: 9, next: null } ------------------- 20 13 100 3 5 9 ----------------After delete at End---------- 20 13 100 3 5 ----------------After delete at Middle---------- 20 13 3 5 ----------------After Reverse Linked List---------- 5 3 13 20 Head ---> Node { value: 5, next: Node { value: 3, next: Node { value: 13, next: [Node] } } } Tail. -> Node { value: 20, next: null } */

class Node { constructor(value) { this.value = value; this.next = null; this.prev = null; } } class DoubleLinkedList { constructor(value) { this.head = this.tail = new Node(value); this.size = 1; } append(value) { const newNode = new Node(value); this.tail.next = newNode; newNode.prev = this.tail; this.tail = newNode; this.size++; } prepend(value) { const newNode = new Node(value); newNode.next = this.head; this.head.prev = newNode; this.head = newNode; this.size++; } insertAtMiddle(value) { if (this.size <= 1) { this.append(value); // If size is 1 or less, append the new node at the end return; } const newNode = new Node(value); const pos = Math.floor(this.size / 2); let counter = 0; let currentNode = this.head; while (currentNode) { if (counter++ === pos) { const nextNode = currentNode.next; currentNode.next = newNode; newNode.prev = currentNode; newNode.next = nextNode; if (nextNode) { nextNode.prev = newNode; } this.size++; break; } currentNode = currentNode.next; } } traverseForward() { let currentNode = this.head; while (currentNode) { console.log(currentNode.value); currentNode = currentNode.next; } } traverseReverse() { let lastNode = this.tail; while (lastNode) { console.log(lastNode.value); lastNode = lastNode.prev; } } deleteAtEnd() { if (this.size === 1) { // Handle the case where there's only one element this.head = this.tail = null; this.size = 0; return; } const lastNode = this.tail; this.tail = lastNode.prev; this.tail.next = null; this.size--; // Optional: nullify references to help garbage collection lastNode.prev = null; } deleteAtMiddle() { if (this.size <= 1) { this.deleteAtEnd(); // If size is 1 or less, simply delete the last element return; } let currentNode = this.head; const pos = Math.floor(this.size / 2); let counter = 0; while (currentNode) { if (counter++ === pos) { const prevNode = currentNode.prev; const nextNode = currentNode.next; if (prevNode) { prevNode.next = nextNode; } if (nextNode) { nextNode.prev = prevNode; } this.size--; // Optional: nullify references to help garbage collection currentNode.next = currentNode.prev = null; break; } currentNode = currentNode.next; } } reverseList() { let currentNode = this.head; let prevNode = null; let nextNode = null; while (currentNode) { nextNode = currentNode.next; currentNode.next = prevNode; currentNode.prev = nextNode; prevNode = currentNode; currentNode = nextNode; } // Swap head and tail this.tail = this.head; this.head = prevNode; } } // Test the implementation const test = new DoubleLinkedList(3); test.append(5); test.append(9); test.prepend(13); test.prepend(20); console.log('Head:', test.head.value); // 20 console.log('Tail:', test.tail.value); // 9 console.log('Size:', test.size); // 5 console.log('-------------------------'); test.traverseForward(); // 20 -> 13 -> 3 -> 5 -> 9 console.log('-------------Reverse Traversal------------'); test.traverseReverse(); // 9 -> 5 -> 3 -> 13 -> 20 console.log('---------Insert At Middle ----------------'); test.insertAtMiddle(100); test.traverseForward(); // 20 -> 13 -> 3 -> 100 -> 5 -> 9 console.log('-------deleteAtEnd-----------'); test.deleteAtEnd(); test.traverseForward(); // 20 -> 13 -> 3 -> 100 -> 5 console.log('-------deleteAtMiddle-----------'); test.deleteAtMiddle(); test.traverseForward(); // 20 -> 13 -> 100 -> 5 console.log('-------Reverse Double Linked List-----------'); test.reverseList(); test.traverseForward(); // 5 -> 100 -> 13 -> 20