LeetCode之Add Two Numbers

问题描述

You are given two non-empty linked lists representing two non-negative integers. 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.

You may assume the two numbers do not contain any leading zero, except the number 0 itself.

Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)
Output: 7 -> 0 -> 8

解题思路：就是实现两个链表依次相加，如果结果大于10，则进一位到后面

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
public class Solution {
    public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
       if (l1==null)
       return l2;
       if (l2==null)
       return l1;
       int carry=0;
       ListNode newhead = new ListNode(-1);
       ListNode l3=newhead;
       while(l1!=null||l2!=null)
       {
           if(l1!=null){
               carry += l1.val;
               l1=l1.next;
           }
           if(l2!=null){
               carry +=l2.val;
               l2=l2.next;
           }
           l3.next=new ListNode(carry%10);
           carry=carry/10;
           l3=l3.next;
       }
       if(carry==1)
        l3.next=new ListNode(1);
        return newhead.next; 
    }
}

代码来源http://www.cnblogs.com/springfor/p/3864493.html