2. Add Two Numbers（链表）

https://leetcode.com/problems/add-two-numbers/description/

题目：模拟整数加法

比较简单，直接附代码

class Solution {
public:
    ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) {

        ListNode *p3=new ListNode(0),*l3=NULL;

        int y=0,add=0;
        while(l1||l2||y){
             add = (l1?l1->val:0) + (l2?l2->val:0) + y;
             y= add / 10;
             p3->next=new ListNode(add % 10);
             if(!l3) l3=p3;
             p3=p3->next;
             l1 = (l1?l1->next:l1);
             l2 = (l2?l2->next:l2);
        }

        return l3->next;
    }
};