// Source : https://oj.leetcode.com/problems/add-two-numbers/

// Author : Hao Chen

// Date : 2014-06-18

/**********************************************************************************

*

* 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

*

**********************************************************************************/

/**

* 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 x=0, y=0, carry=0, sum=0;

ListNode *h=NULL, **t=&h;

while (l1!=NULL || l2!=NULL){

x = getValueAndMoveNext(l1);

y = getValueAndMoveNext(l2);

sum = carry + x + y;

ListNode *node = new ListNode(sum%10);

*t = node;

t = (&node->next);

carry = sum/10;

}

if (carry > 0) {

ListNode *node = new ListNode(carry%10);

*t = node;

}

return h;

}

private:

int getValueAndMoveNext(ListNode* &l){

int x = 0;

if (l != NULL){

x = l->val;

l = l->next;

}

return x;

}

};