백준 11659: 구간 합 구하기 4

#include <iostream>
#include <vector>
using namespace std;

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

	int N, M, i, tmp, start, end;
	vector<int> sum; // sum[i]: i번째 값까지의 합
	int now;
	cin >> N >> M;

	now = 0;
	sum.push_back(now);
	for (i = 0; i < N; i++) {
		cin >> tmp;
		now += tmp;
		sum.push_back(now);
	}

	for (i = 0; i < M; i++) {
		cin >> start >> end;
		cout << sum[end] - sum[start - 1] << "\n";
	}
	return 0;
}