# Add Two Numbers - Daily JS (Day 22)

Problem Statement
You are given two non-empty linked lists representing two non-negative integers. The digits are stored in reverse order, and each of their nodes contains a single digit. Add the two numbers and return the sum as a linked list.

You may assume the two numbers do not contain any leading zero, except the number 0 itself.

``````Input: l1 = [2,4,3], l2 = [5,6,4]
Output: [7,0,8]
Explanation: 342 + 465 = 807.
``````

Example 2:

``````Input: l1 = , l2 = 
Output: 
``````

Example 3:

``````Input: l1 = [9,9,9,9,9,9,9], l2 = [9,9,9,9]
Output: [8,9,9,9,0,0,0,1]
``````

Constraints:

• The number of nodes in each linked list is in the range [1, 100].
• `0 <= Node.val <= 9`
• It is guaranteed that the list represents a number that does not have leading zeros.

Solution

``````/**
* function ListNode(val, next) {
*     this.val = (val===undefined ? 0 : val)
*     this.next = (next===undefined ? null : next)
* }
*/
/**
* @param {ListNode} l1
* @param {ListNode} l2
* @return {ListNode}
*/
var addTwoNumbers = function(l1, l2) {
if (l1 == null && l2 == null) return 0;
let dummie = new ListNode();
let node = dummie;
let carrier = false;
while (l1 || l2 || carrier) {
let new_value = 0;
// sum nodes if availible
if (l1) [new_value, l1] = [new_value + l1.val, l1.next];
if (l2) [new_value, l2] = [new_value + l2.val, l2.next];
// take care of the carrier
if (carrier) [new_value, carrier] = [new_value + 1, false];
if (new_value >= 10) carrier = true;
// append new node
node.next = new ListNode(new_value % 10);
node = node.next;
}
return dummie.next;
};
``````

LeetCode issue: