1.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

2.解法分析

题目很简单，不用描述了。

/**

* 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) {

// Start typing your C/C++ solution below

// DO NOT write int main() function

ListNode *cur1=l1;

ListNode *cur2=l2;

int carrier=0;

int curDigit=0;

ListNode *head;

int flag = 0;

ListNode *prev;

while(cur1!=NULL&&cur2!=NULL)

{

curDigit=(cur1->val+cur2->val+carrier)%10;

carrier=(cur1->val+cur2->val+carrier)/10;

ListNode *cur=new ListNode(curDigit);

if(flag==0)

{

head=cur;

prev=cur;

flag =1;

}

else

{

prev->next=cur;

prev=cur;

}

cur1=cur1->next;

cur2=cur2->next;

}

if(cur1!=NULL||cur2!=NULL)

{

cur1=cur1!=NULL?cur1:cur2;

while(cur1!=NULL)

{

curDigit=(cur1->val+carrier)%10;

carrier=(cur1->val+carrier)/10;

ListNode *cur=new ListNode(curDigit);

prev->next=cur;

prev=cur;

cur1=cur1->next;

}

}

if(carrier!=0)

{

ListNode *cur=new ListNode(carrier);

prev->next=cur;

}

return head;

}

};