백준 10986 c++

#include <iostream>
#include <vector>

using namespace std;

int main(void)
{
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);

	int N, M;
	long long int result = 0;
	long long int temp;
	long long int sum = 0;
	int i;

	cin >> N >> M;
	vector <long long int> vi(M, 0);
	for (i = 0; i < N; i++)
	{
		cin >> temp;
		sum = sum + temp;
		if (sum % M == 0)
		{
			result++;
		}
		else
		{
			;
		}
		vi[sum % M]++;
	}
	for (i = 0; i < M; i++)
	{
		result = result + ((vi[i] * (vi[i] - 1)) / 2);
	}
	cout << result << "\n";

	return 0;
}