题目链接
https://leetcode.cn/problems/add-two-numbers/description/
解答过程
这个题目本身难度不大，主要考察的是基本的链表操作能力，与合并两个有序链表有一定相似之处。
public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
ListNode dummy = new ListNode(-1), tail = dummy;
int carry = 0;
while (l1 != null || l2 != null) {
int val1 = l1 != null ? l1.val : 0;
int val2 = l2 != null ? l2.val : 0;
int val = (val1 + val2 + carry) % 10;
carry = (val1 + val2 + carry) / 10;
tail.next = new ListNode(val);
tail = tail.next;
if (l1 != null) {
l1 = l1.next;
}
if (l2 != null) {
l2 = l2.next;
}
}
if (carry == 1) {
tail.next = new ListNode(1);
}
return dummy.next;
}