#include <gtest/gtest.h>

using namespace std;

struct ListNode {

    int val;

    ListNode *next;

    ListNode(int x) :

        val(x), next(NULL)

    {}

};

ListNode* addTwoNumbers(ListNode* l1, ListNode* l2)

{

    ListNode* result = 0;

    ListNode* current = 0;

    int carry = 0;

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

    {

        int value = 0;

        if (l1 != NULL)

        {

            value += l1->val;

            l1 = l1->next;

        }

        if (l2 != NULL)

        {

            value += l2->val;

            l2 = l2->next;

        }

        if (current == NULL)

        {

            current = result = new ListNode(value % 10);

            carry = value / 10;

        }

        else

        {

            current->next = new ListNode((value + carry) % 10);

            carry = (value + carry) / 10;

            current = current->next;

        }

    }

    if (carry)

    {

        if (current == NULL)

        {

            current = result = new ListNode(carry);

        }

        else

        {

            current->next = new ListNode(carry);

            current = current->next;

        }

    }

    return result;

}

TEST(Pratices, tAddTwoNumbers)

{

    // (2 -> 4 -> 3) + (5 -> 6 -> 4)  7 -> 0 -> 8

    ListNode* l1 = new ListNode(2);

    l1->next = new ListNode(4);

    l1->next->next = new ListNode(3);

    ListNode* l2 = new ListNode(5);

    l2->next = new ListNode(6);

    l2->next->next = new ListNode(4);

    ListNode* result = addTwoNumbers(l1,l2);

    // NULL + (2 -> 4 -> 3)

    result = addTwoNumbers(NULL,l1);

    // (2 -> 4 -> 3) + (5 -> 6 -> 4 -> 4)

    l2->next->next->next = new ListNode(4);

    result = addTwoNumbers(l1,l2);

    // 1 + 9->9

    l1 = new ListNode(1);

    l2 = new ListNode(9);

    l2->next = new ListNode(9);

    result = addTwoNumbers(l1,l2);

}