题目描述

You are given two linked lists representing two non-negative numbers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return it as a linked list.
Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)Output: 7 -> 0 -> 8

我的解答

public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
        int carry = 0;
        ListNode newHead = new ListNode(0);
        ListNode p1 = l1,p2=l2,p3=newHead;
        while (p1 != null || p2 != null){
            if(p1 != null){
                carry += p1.val;
                p1 = p1.next;
            }
            if(p2 != null){
                carry += p2.val;
                p2 = p2.next;
            }
            p3.next = new ListNode(carry%10);
            carry /= 10;
            p3 = p3.next;
        }
        if(carry == 1){
            p3.next = new ListNode(1);
        }
        return newHead.next;
    }

public class ListNode {
     int val;
     ListNode next;
     ListNode(int x) { val = x; }
}

分析

这道题比较容易，为简单链表题，主要用carry来维护所加的结果，需要注意的情况是当一个链表已经结束而另一个还未结束的情况，还有全部遍历完之后看下carry是否为1，如果为1要在后面多加一位。