백준:수들의합2

#include <iostream>
#include <vector>

using namespace std;
int N, M;
vector<int>arr;
int main() {
	freopen_s(new FILE*, "input.txt", "r", stdin);
	cin >> N >> M;
	arr.resize(N);
	for (int i = 0; i < N; i++) {
		cin >> arr[i];
	}
	int start = 0;
	int end = 0;
	int sum = arr[end];
	int answer = 0;
	while (end < N) {
		if (sum < M) {
			end++;
			if (end < N) {
				sum += arr[end];
			}
			else if (sum > M) {
				sum -= arr[start];
				start++;
			}
			else if (sum == M) {
				sum -= arr[start];
				start++;
				end++;
				if (end < N) {
					sum += arr[end];
				}
				answer++;
			}
			

		}


	}
	cout << answer << "\n";
	return 0;
}

어느부분을 수정해야지,,, 디버깅 해봐야겠다 ㅠㅠ