LeetCode 两数相加

/**
 * 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 resNode = new ListNode(0);
        ListNode resNext = resNode;
        int carry = 0;

        while (l1 != null || l2 != null) {

            int sum = carry;
            if (l1 != null) {
                sum += l1.val;
                l1 = l1.next;
            }
            if (l2 != null) {
                sum += l2.val;
                l2 = l2.next;
            }

            int val = sum < 10 ? sum : sum - 10;
            carry = sum < 10 ? 0 : 1;

            resNext.next = new ListNode(val);
            resNext = resNext.next;
        }

        if (carry != 0) {
            resNext.next = new ListNode(1);
        }

        return resNode.next;
    }
}