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 -> 8Explanation:342 + 465 = 807.

### Solution

/** * Definition for singly-linked list. * public class ListNode { * int val; * ListNode next; * ListNode(int x) { val = x; } * } */ class Solution { public ListNode addTwoNumbers(ListNode l1, ListNode l2) { ListNode dummy = new ListNode(0); ListNode head = dummy; int carry = 0; while(l1 != null || l2 != null) { int val1 = (l1 != null) ? l1.val : 0; int val2 = (l2 != null) ? l2.val : 0; int sum = val1 + val2 + carry; carry = sum/10; ListNode newNode = new ListNode(sum%10); head.next = newNode; head = head.next; l1 = (l1 != null) ? l1.next : l1; l2 = (l2 != null) ? l2.next : l2; } if(carry != 0) head.next = new ListNode(carry); return dummy.next; } }