class Node {
constructor(value) {
this.value = value;
this.next = null;
}
}
class LinkedList {
constructor(value) {
this.head = new Node(value);
this.tail = this.head;
this.length = 1;
}
printList() {
const array = [];
let currentNode = this.head;
while( currentNode !== null ) {
array.push(currentNode.value);
currentNode = currentNode.next;
}
return array;
}
prepend(value) {
const newNode = new Node(value);
newNode.next = this.head;
this.head = newNode;
this.length++;
}
append(value) {
const newNode = new Node(value);
this.tail.next = newNode;
this.tail = newNode;
this.length++;
}
insert(value, index) {
if(index >= this.length) {
return this.append(value);
}
const newNode = new Node(value);
let leader = this._traverseToIndex(index - 1);
newNode.next = leader.next;
leader.next = newNode;
this.length++;
}
remove(index) {
if( index >= this.length || index < 0) {
return 'out of bounds index';
}
if( index === 0 ) {
this.head = this.head.next;
}
else {
let leader = this._traverseToIndex(index -1);
let unwantedNode = leader.next;
leader.next = unwantedNode.next;
}
this.length--;
}
reverse() {
if( linkedList.length <= 1) {
return linkedList;
}
let prevNode = this.head;
let currentNode = this.head.next;
let nextNode = currentNode.next;
prevNode.next = null;
currentNode.next = prevNode;
while( nextNode !== null ) {
prevNode = currentNode;
currentNode = nextNode;
nextNode = nextNode.next;
currentNode.next = prevNode;
}
let newTail = this.head;
this.head = currentNode;
this.tail = newTail;
}
_traverseToIndex(index){
let counter = 0;
let currentNode = this.head;
while( counter < index ) {
currentNode = currentNode.next;
counter++;
}
return currentNode;
}
}
const linkedList = new LinkedList(5);
linkedList.prepend(4)
linkedList.append(8);
linkedList.insert(6,3)
linkedList.append(17);
linkedList.remove(1);
linkedList.reverse();
console.log(linkedList.printList())
