# Failed submission

• Recently I started practicing coding on this website and I have a problem with code submission that there shows message "Line 57: redefinition of ‘int main()’." everytime I submit my solution.

I do not know why and the code itself works fine on my computer.

Here is the code

``````#include <vector>
``````

#include <iostream>

using namespace std;

class Solution {
public:
vector<int> twoSum(vector<int>& nums, int target) {
vector<int> index_1_result, index_2_result;
int i, j, number_1, number_2, sum;

``````	int length_input = nums.size();

// Find all the possible combination;

for (i = 0; i < length_input; i++){
number_1 = nums.at(i);
for (j = i + 1; j < length_input; j++){
number_2 = nums.at(j);
sum = number_1 + number_2;
if (sum == target){
cout << "number 1 = " << number_1 << "\n";
cout << "number 2 = " << number_2 << "\n";
index_1_result.push_back(i + 1);
index_2_result.push_back(j + 1);
}
}
}

vector<int> result_return;

// Since there is only a result by assumption;

result_return.push_back(index_1_result.at(0));
result_return.push_back(index_2_result.at(0));
return result_return;
}
``````

};

int main(){

``````Solution solution1;
vector<int> nums, result;

nums.push_back(2);
nums.push_back(7);
nums.push_back(11);
nums.push_back(15);

int target = 9;

result = solution1.twoSum(nums, target);

cout << "index1 = " << result.at(0) << ", " << "index2 = " << result.at(1) << "\n";
return 0;
``````

}

• what you should do is commit your algorithms, the function twoSum, you should not commit the main function, leetcode will provide the entry of program ,I think. I hope this answer can help you.(I am chinese , my english is not pretty good, I hope you can understand what I say.)