leetCode2

 1 /**
 2  * Definition for singly-linked list.
 3  * public class ListNode {
 4  *     int val;
 5  *     ListNode next;
 6  *     ListNode(int x) { val = x; }
 7  * }
 8  */
 9 class Solution {
10     public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
11          ListNode p1 = l1,p2=l2;
12         ListNode dummy = new ListNode(0);
13         ListNode cur = dummy;
14         int sum = 0 ;
15         while (p1!=null||p2!=null){
16             if(p1!=null){
17                 sum+=p1.val;
18                 p1=p1.next;
19             }
20             if(p2!=null){
21                 sum+=p2.val;
22                 p2=p2.next;
23             }
24             cur.next = new ListNode(sum%10);
25             sum/=10;
26             cur=cur.next;
27         }
28         if(sum==1){
29             cur.next=new ListNode(1);
30         }
31 
32         return dummy.next;
33     }
34 }