[LeetCode]2.两数相加

题目

解法

/**
 * 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 dummyHead = new ListNode(0);
        ListNode p = l1, q = l2, cur = dummyHead;
        int carry = 0;
        while(p != null || q!= null){
            int x = (p != null) ? p.val : 0;
            int y = (q != null) ? q.val : 0;
            int sum = x + y + carry;
            carry = sum/10;
            cur.next = new ListNode(sum%10);
            cur = cur.next;
            if(p!=null)p=p.next;
            if(q!=null)q=q.next;
        }
        if(carry > 0){
            cur.next = new ListNode(carry);
        }
        return dummyHead.next;
    }
}

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

总结

可以使用哑点来简化代码，使用变量跟踪进位，要注意链表长短不一的情况.
上面是官方解法，我自己的思路是先判断输入链表长度补全短链表，再进行求和,最后代码冗长…继续刷题吧