c++-add two numbers 两个链表相加

题目描述

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

这道题考察的是链表相加，最简单的方法就是用新的链表来存入数据，因此关键点在于链表的新建：

利用new来开辟存储空间，也就是堆：

/*** 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) {int temp;int flag=0;ListNode* p=l1;ListNode* q=l2;ListNode* res_head = new ListNode(-1);ListNode* res_tmp=res_head;while(p!=NULL || q!=NULL || flag){temp=(p?p->val:0)+(q?q->val:0)+flag;flag=0;if(temp>=10){temp-=10;flag=1;}ListNode* tmp = new ListNode(temp);res_tmp->next=tmp;res_tmp=res_tmp->next;if(p) p = p->next;if(q) q = q->next;}return res_head->next;}
};