LeetCode --- 2. 两数相加

• LeetCode链接：2. 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) {
        int flag = 0;
        ListNode dummyNode = new ListNode(-1);
        ListNode curNode = dummyNode;
        while (l1 != null || l2 != null) {
            int sum = 0;
            if (l1 != null) {
                sum += l1.val;
                l1 = l1.next;
            }
            if (l2 != null) {
                sum += l2.val;
                l2 = l2.next;
            }
            sum += flag;
            flag = sum / 10;
            curNode.next = new ListNode(sum % 10);
            curNode = curNode.next;
        }
        if (flag > 0) {
            curNode.next = new ListNode(flag);
        }
        return dummyNode.next;
    }
}