leetcode_2 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.

解法

题目显然让链表去加，也是大数据运算的一种思路，有人直接遍历出数字用加法，显然会超范围。

/**
 * 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 result = new ListNode(0);
        ListNode init = result;
        while (true) {
            int sum = l1.val + l2.val + result.val;
            if (sum > 9) {
                result.val = sum - 10;
                result.next = new ListNode(1);
            } else {
                result.val = sum;
                result.next = new ListNode(0);
            }
            if (l1.next == null && l2.next == null) {
                if(result.next.val == 0){
                    result.next = null;
                }
                break;
            } else {
                result = result.next;
            }
            if (l1.next == null) {
                l1.val = 0;
            } else {
                l1 = l1.next;
            }
            if (l2.next == null) {
                l2.val = 0;
            } else {
                l2 = l2.next;
            }
        }
        return init;
    }
}