AddTwoNumbers.js

/**
 * A LinkedList based solution for Add Two Numbers
 *
 */
import { Node } from './SinglyLinkedList.js'

/*
Problem Statement:
Given two non-empty linked lists representing two non-negative integers.
The digits are stored in reverse order and each of their nodes contain a single digit.
Add the two numbers and return it as a linked list.

Link for the Problem: https://leetcode.com/problems/add-two-numbers/
*/

class AddTwoNumbers {
 constructor() {
 this.dummyNode = new Node(0)
 }

 solution(firstList, secondList) {
 let firstRunner = firstList
 let secondRunner = secondList
 let tail = this.dummyNode
 let carry = 0
 while (firstRunner != null || secondRunner != null) {
 const firstNumber = firstRunner ? firstRunner.data : 0
 const secondNumber = secondRunner ? secondRunner.data : 0
 const sum = carry + firstNumber + secondNumber
 carry = parseInt(sum / 10)
 tail.next = new Node(sum % 10)
 tail = tail.next
 if (firstRunner) {
 firstRunner = firstRunner.next
 }
 if (secondRunner) {
 secondRunner = secondRunner.next
 }
 }
 if (carry > 0) {
 tail.next = new Node(carry % 10)
 }

 return this.dummyNode.next
 }

 solutionToArray() {
 const list = []
 let currentNode = this.dummyNode.next
 while (currentNode) {
 list.push(currentNode.data)
 currentNode = currentNode.next
 }

 return list
 }
}

export { AddTwoNumbers }