leetcode-solutions-with-javascript/add-two-numbers.js at develop · imtomq/leetcode-solutions-with-javascript · GitHub

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/**
 * Definition for singly-linked list.
 * function ListNode(val, next) {
 *     this.val = (val===undefined ? 0 : val)
 *     this.next = (next===undefined ? null : next)
 * }
 */
/**
 * @param {ListNode} list1
 * @param {ListNode} list2
 * @return {ListNode}
 */

// https://leetcode.com/problems/add-two-numbers/

function ListNode(val, next) {
  this.val = val === undefined ? 0 : val;
  this.next = next === undefined ? null : next;
}

// var addTwoNumbers = function (list1, list2) {
//   const list3 = new ListNode();
//   let prev = list3;
//   let surplus = 0;
//   let sum = 0;

//   while (list1 || list2) {
//     sum = (list1?.val || 0) + (list2?.val || 0) + surplus;
//     if (sum >= 10) {
//       prev.next = new ListNode(sum - 10);
//       surplus = 1;
//     } else {
//       surplus = 0;
//       prev.next = new ListNode(sum);
//     }
//     list1 = list1?.next || 0;
//     list2 = list2?.next || 0;
//     prev = prev.next;
//   }
//     if (surplus) {
//         prev.next = new ListNode(1);
//     }
//   return list3.next;
// };

var addTwoNumbers = function (list1, list2) {
  const listnode = new ListNode();
  let head = listnode;
  let carry = 0;

  while (list1 || list2 || carry) {
    let sum = carry;
    if (list1) {
      sum += list1.val;
      list1 = list1.next;
    }
    if (list2) {
      sum += list2.val;
      list2 = list2.next;
    }

    carry = Math.floor(sum / 10);
    head.next = new ListNode(sum % 10);
    head = head.next;
  }

  return listnode.next;
};

// create first linked list: 1 -> 3 -> 10
var n3 = new ListNode(5, null);
var n2 = new ListNode(3, n3);
var n1 = new ListNode(1, n2);
var L1 = n1;

// create second linked list: 5 -> 6 -> 9
var n6 = new ListNode(9, null);
var n5 = new ListNode(6, n6);
var n4 = new ListNode(5, n5);
var L2 = n4;

addTwoNumbers(L1, L2);