leetcode-2.两数相加

题目

https://leetcode-cn.com/problems/add-two-numbers/description/

代码

/*
 * @lc app=leetcode.cn id=2 lang=java
 *
 * [2] 两数相加
 */

// @lc code=start
/**
 * 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 p = new ListNode(-1);
        ListNode head = p;
        
        int add = 0;
        while (l1 != null && l2 != null) {
            int vv = l1.val + l2.val + add;
            if (vv >= 10) {
                add = 1;
                vv = vv - 10;
            } else {
                add = 0;
            }
            ListNode newNode = new ListNode(vv);
            p.next = newNode;
            p = p.next;
            l1 = l1.next;
            l2 = l2.next;
        }

        ListNode temp = l1 != null ? l1 : l2;
        while (temp != null) {
            int vv = temp.val + add;
            if (vv >= 10) {
                add = 1;
                vv = vv - 10;
            } else {
                add = 0;
            }
            ListNode newNode = new ListNode(vv);
            p.next = newNode;
            p = p.next;
            temp = temp.next;
        }

        if (add == 1) {
            ListNode newNode = new ListNode(1);
            p.next = newNode;
            p = p.next;
        }
        return head.next;
    }

}
// @lc code=end