题目没有说清楚，trick挺多，考察细心程度的水题吧。
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
代码语言：javascript复制/**
* 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=new ListNode(0);
ListNode* slide=result;
int cnt=0;
while(l1!=NULL || l2!=NULL)//两个链表可能不一样长，不够的时候短的当作0
{
int vala=0,valb=0;
if(l1!=NULL)
{
vala=l1->val;
l1=l1->next;
}
if(l2!=NULL)
{
valb=l2->val;
l2=l2->next;
}
ListNode* temp=new ListNode((vala valb cnt));
cnt=(vala valb cnt)/10;
slide->next=temp;
slide=slide->next;
}
if(cnt!=0)//最后剩下的进位也要新建一个节点存放
{
ListNode* temp=new ListNode(cnt);
slide->next=temp;
}
return result->next;
}
};
