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.
Example 1:
Input: l1 = [2,4,3], l2 = [5,6,4]
Output: [7,0,8]
Explanation: 342 + 465 = 807.
Example 2:
Input: l1 = [0], l2 = [0]
Output: [0]
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.
/**
* Definition for singly-linked list.
* 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) {
let head = new ListNode();
let temp = head;
let sum = 0;
let carry = 0;
while (l1 !== null || l2 !== null) {
sum = carry + (l1 !== null ? l1.val : 0) + (l2 !== null ? l2.val : 0);
carry = sum >= 10 ? 1 : 0;
sum = sum % 10;
temp.next = new ListNode(sum);
temp = temp.next;
if (l1) l1 = l1.next;
if (l2) l2 = l2.next;
if (carry) temp.next = new ListNode(carry);
}
return head.next;
};