[leetcode] add two numbers（大数据加法链表版）

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

题意：输入两个链表，对应位相加，并且进位到下一位。

/** * 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 *ans = new ListNode(0), *p = ans;        int cur = 0;        while(l1 != NULL || l2 != NULL || cur)        {            p->val = (l1 ? l1->val : 0) + (l2 ? l2->val : 0) + cur;            cur = p->val / 10;            p->val %= 10;            if(l1) l1 = l1->next;            if(l2) l2 = l2->next;            if(l1 || l2 || cur)                p->next = new ListNode(0);            p = p->next;        }        return ans;    }};