LinkedList.ts

linkedList.ts

import LinkedListNode from './linkedListNode';

export default class LinkedList {
  private headSentinel;

  constructor() {
    this.headSentinel = new LinkedListNode(null);
  }

  head() {
    return this.headSentinel.next;
  }

  find(index: number) {
    if (index == -1) {
      return this.headSentinel;
    }
    let ele = this.head();
    for (let i = 0; i < index; i ++) {
      ele = ele.next;
    }

    return ele;
  }

  insert(index: number, node: LinkedListNode) {
    let preEle = this.find(index - 1);
    let postEle = this.find(index);
    node.next = postEle;
    preEle.next = node;
  }

  delete(index: number) {
    let preEle = this.find(index - 1);
    let eleToDel = preEle.next;
    let postEle = eleToDel.next;
    preEle.next = postEle;
    eleToDel.next = null;
  }

  print() {
    let ele = this.head();
    while (ele !== undefined) {
      console.log(ele.value);
      ele = ele.next;
    }
  }
}

linkedListImplementation.ts

import LinkedListNode from "./linkedListNode";
import LinkedList from "./linkedList";

let ll = new LinkedList;
let n1 = new LinkedListNode(1);
ll.insert(0, n1);
let n2 = new LinkedListNode(2);
ll.insert(0, n2);
let n3 = new LinkedListNode(3);
ll.insert(0, n3);
let n4 = new LinkedListNode(4);
ll.insert(1, n4);
ll.print();

ll.delete(1);
ll.print();

linkedListNode.ts

export default class LinkedListNode {
  public next: LinkedListNode;
  constructor(public value: any) {}
}