Problem Description:

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

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
public:
    ListNode *addTwoNumbers(ListNode *l1, ListNode *l2) {
        ListNode *p=l1, *q=l2;
        ListNode *head=NULL,*cur=NULL;
        if(!p&&!q)
            return head;
        int flag=0;
        while(p&&q)
        {
            int value=http://www.mamicode.com/(p->val+q->val+flag)%10;>