Add Two Numbers

题目

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

译文

给你两个代表两个非负数字的链表。每位数倒序存储在链表中，每个节点是一位数。返回两个数的加数的链表。

分析

medium

我的代码

struct ListNode{    int val;    ListNode *next;    ListNode(int x) : val(x), next(NULL){}};class Solution{    public:        ListNode* addTwoNumbers(ListNode* l1, ListNode* l2){            if(l1==NULL)return l2;            if(l2==NULL)return l1;            int val1 = 0, val2 = 0, carry = 0, temp = 0;            ListNode *tail = new ListNode(0);            ListNode *ptr = tail;            while(l1!=NULL || l2!=NULL){                if(l1!=NULL){                    val1 = l1->val;                    l1 = l1->next;                }                else{                    val1 = 0;                }                if(l2!=NULL){                    val2 = l2->val;                    l2 = l2->next;                }                else{                    val2 = 0;                }                temp = val1 + val2 + carry;                ptr->next =new ListNode(temp % 10);                carry = temp / 10;                ptr = ptr->next;                cout<<ptr->val<<",";            }            if(carry == 1){                ptr->next = new ListNode(1);                cout<<ptr->next->val<<endl;            }            return tail->next;        }};