https://www.acmicpc.net/problem/11659
#include <iostream>
#include <vector>
using namespace std;
int main(void)
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int N, M;
cin >> N >> M;
vector<long long> accum(N+1);
long long tmp, inter_i, inter_j;
for (int i = 1; i <= N; i++)
{
cin >> tmp;
accum[i] = accum[i - 1] + tmp;
}
for (int i = 0; i < M; i++)
{
cin >> inter_i >> inter_j;
cout << accum[inter_j] - accum[inter_i - 1] << "\n";
}
return 0;
}