You are given two non-empty linked lists representing two non-negative integers. 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.

You may assume the two numbers do not contain any leading zero, except the number 0 itself.

Example

Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)
Output: 7 -> 0 -> 8
Explanation: 342 + 465 = 807.

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;
ListNode* res = new ListNode((l1->val+l2->val)%10);
ListNode* pNode = res;
int carry = (l1->val+l2->val)/10;
while (l1->next || l2->next || carry)
{
int v1=0,v2 = 0;
if (l1->next)
{
v1 = l1->next->val;
l1 = l1->next;
}
if (l2->next)
{
v2 = l2->next->val;
l2 = l2->next;
}
ListNode* node = new ListNode((v1+v2+carry)%10);
carry = (v1+v2+carry)/10;
pNode->next = node;
pNode = node;
}
return res;
}
};