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

代码：

// AddTwoNumbers.cpp : 定义控制台应用程序的入口点。//#include "stdafx.h"#include
     
      using namespace std;struct ListNode {	int val;	ListNode *next;	ListNode(int x) : val(x), next(NULL) {}	};class Solution {public:	ListNode *addTwoNumbers(ListNode *l1, ListNode *l2) {		ListNode *res,*p;		int plus = 0,sum=0;		res = new ListNode(0);		p = res;		while (l1 != NULL&&l2 != NULL)		{			sum = l1->val + l2->val+plus;			//p = new ListNode(sum % 10);			p->val = sum % 10;			plus = sum / 10;						l1 = l1->next;			l2 = l2->next;			if (l1 != NULL&&l2 != NULL)			{				ListNode *temp = new ListNode(0);				p->next = temp;				p = p->next;			}		}		if (l1 == NULL&&l2 == NULL)		{			if (plus != 0)			{				ListNode *temp = new ListNode(plus);				p->next = temp;				p = p->next;			}		}		else if (l1 == NULL)		{			while (l2 != NULL)			{				sum =l2->val + plus;				ListNode *temp = new ListNode(sum % 10);				plus = sum / 10;				p->next = temp;				p = p->next;				l2 = l2->next;			}			if (plus != 0)			{				ListNode *temp = new ListNode(plus);				p->next = temp;				p = p->next;			}		}		else if (l2 == NULL)		{			while (l1 != NULL)			{				sum = l1->val + plus;				ListNode *temp = new ListNode(sum % 10);				plus = sum / 10;				p->next = temp;				p = p->next;				l1 = l1->next;			}			if (plus != 0)			{				ListNode *temp = new ListNode(plus);				p->next = temp;				p = p->next;			}		}		return res;	}};int _tmain(int argc, _TCHAR* argv[]){	ListNode *l1 = new ListNode(1);	//ListNode *l2 = new ListNode(4);	//ListNode *l3 = new ListNode(3);	//l1->next = l2;	//l2->next = l3;	ListNode *ll1 = new ListNode(9);	ListNode *ll2 = new ListNode(9);	//ListNode *ll3 = new ListNode(4);	ll1->next = ll2;	//ll2->next = ll3;	Solution ss;	ListNode *res = ss.addTwoNumbers(l1,ll1);	while (res != NULL)	{		cout << res->val << "";		res = res->next;	}	system("pause");	return 0;}