LeetCode 2 Add Two Numbers

原创：http://blog.csdn.net/u013383042/article/details/50757591

题目：

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.

/**
* 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) {
int carry = 0;
ListNode listNode = new ListNode(0);
ListNode p1 = l1,p2 = l2,p3 = listNode;

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);
p3 = p3.next;
carry /= 10;
}
if(carry == 1)
{
p3.next = new ListNode(1);
}

return listNode.next;
}
}