Leetcode2---Add Two Numbers

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 contain a single digit. Add the two numbers and return it as a linked list.

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

Example

Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)
Output: 7 -> 0 -> 8
Explanation: 342 + 465 = 807.

 1 /**
 2  * Definition for singly-linked list.
 3  * function ListNode(val) {
 4  *     this.val = val;
 5  *     this.next = null;
 6  * }
 7  */
 8 /**
 9  * @param {ListNode} l1
10  * @param {ListNode} l2
11  * @return {ListNode}
12  */
13 var addTwoNumbers = function(l1, l2) {
14     // curry表示进位
15     var curry = 0;
16     var head = new ListNode(0);
17     var res = head;
18     
19     while(l1 || l2) {
20         var val1 = l1 ? l1.val : 0;
21         var val2 = l2 ? l2.val : 0;
22         l1 = l1 ? l1.next : null;
23         l2 = l2 ? l2.next : null;
24         
25         var val = val1 + val2 + curry;
26         curry = parseInt(val / 10);
27         val = val % 10;
28 
29         var node = new ListNode(val);
30         head.next = node;
31         head = head.next;
32     }
33     if(curry > 0) {
34         var node = new ListNode(curry);
35         head.next = node;
36     }
37     return res.next;
38 };