No2.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

/** * 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 * result= NULL;ListNode * p1=l1,*p2=l2;ListNode * pNew = NULL, * last = NULL;int pro =0;int val1=0 ,val2=0;while(p1 || p2)        {                if(p1)                {                    val1 =p1->val;                }else val1 =0;                if(p2)                {                    val2 =p2->val;                }else val2 =0;pNew =new ListNode(0);pNew->val = val1 + val2 + pro;if( 9 < pNew->val ){ pNew->val -=10; pro=1; }elsepro=0;if(!result){result = pNew;last = pNew;}else{last->next = pNew;last = pNew;}if(p1)p1 = p1->next;if(p2)p2=  p2->next;}if(pro > 0){    pNew =new ListNode(pro);    last->next = pNew;}return result;    }};