[leetcode] Add Two Numbers

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

#include <iostream>
#include <map>
#include <vector>
#include <string>

using namespace std;

 struct ListNode {
     int val;
     ListNode *next;
     ListNode(int x) : val(x), next(NULL) {}
 };

class Solution {
public:
    ListNode *addTwoNumbers(ListNode *l1, ListNode *l2) {
        ListNode* current_result = new ListNode(0);
        current_result->next = l1;
        ListNode* result = l1;
        int val;

        int over_ten_flag = 0;

        while(l1){
            if(l2){
                val = (over_ten_flag + l1->val + l2->val) % 10;
                over_ten_flag = (over_ten_flag + l1->val + l2->val) / 10;
                l2 = l2->next;
            } else{
                break;
            }
            current_result->next->val = val;
            current_result = current_result->next;
            l1 = l1->next;
        }

        while(l1){
            if ( l1->val != 9 || over_ten_flag == 0 ){
                current_result->next->val = current_result->next->val + over_ten_flag;
                over_ten_flag = 0;
                break;
            }
            current_result->next->val = 0;
            current_result = current_result->next;
            l1 = l1->next;
        }

        if(l2) {
            current_result->next = l2;

     while(l2){
                if ( l2->val != 9 || over_ten_flag == 0 ){
                    current_result->next->val = current_result->next->val + over_ten_flag;
                    over_ten_flag = 0;
                    break;
                }
                current_result->next->val = 0;
                current_result = current_result->next;
                l2 = l2->next;
     }
        }

        if(over_ten_flag){
            ListNode* temp_node = new ListNode(1);
            current_result->next = temp_node;
        }

        return result;
    }
};

int main(){
    Solution* a = new Solution();
    ListNode* n1 = new ListNode(5);
    ListNode* n2 = new ListNode(4);
    ListNode* n3 = new ListNode(3);
    ListNode* n4 = new ListNode(5);
    ListNode* n5 = new ListNode(6);
    ListNode* n6 = new ListNode(4);

    n1->next = n2;
//    n2->next = n3;

//    n4->next = n5;
//    n5->next = n6;

    ListNode* result = a->addTwoNumbers(n1, n4);

    cout << result->val << result->next->val << endl;

    bool negtive = 3>0;
    cout << negtive;

    system("pause");
    return 0;
}