leetcode：Add Two Numbers

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

解决方法（java版）

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) {
 *         val = x;
 *         next = null;
 *     }
 * }
 */
 
class Solution {
    public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
        List<ListNode> list=new LinkedList<ListNode>();
        int valuenext=0;
        while(l1!=null&&l2!=null){
         int value=(valuenext+l1.val+l2.val)%10;
         //valuenext=0;
         valuenext=(l1.val+l2.val+valuenext)/10;
         list.add(new ListNode(value));
         l1=l1.next;
         l2=l2.next;
        }
         if(l1==null&&l2!=null){
         while(l2!=null){
             int value=(valuenext+l2.val)%10;
             valuenext=(l2.val+valuenext)/10;
             list.add(new ListNode(value));
          l2=l2.next;
         }
        }
        else if(l2==null&&l1!=null){
         while(l1!=null){
             int value=(valuenext+l1.val)%10;
             valuenext=(l1.val+valuenext)/10;
             list.add(new ListNode(value));
          l1=l1.next;
         }      
        }
        if(valuenext!=0&&l1==null&&l2==null){
          list.add(new ListNode(valuenext));
         }
        for(int i=0;i<list.size()-1;i++){
          list.get(i).next=list.get(i+1);
        }
        return list.get(0);
    }
}