试题传送门

#include <bits/stdc++.h>

using namespace std;
const int N = 100010;
int q[N];
int s[N];
//一维前缀和
int main() {//优化输入
    ios::sync_with_stdio(false);
    int n, m;
    cin >> n >> m;
    for (int i = 1; i <= n; i++) {
        cin >> q[i];
        s[i] = s[i - 1] + q[i];
    }
    while (m--) {
        int l, r;
        cin >> l >> r;
        printf("%d\n", s[r] - s[l - 1]);
    }
    return 0;
}