题解 | #【模板】前缀和#

#include <iostream>
using namespace std;
const int N = 100010;
long long a[N], s[N];

int main() {
    int n, m;
    cin >> n >> m;
    for(int i = 1; i <= n; i ++){
        cin >> a[i];
        s[i] = s[i - 1] + a[i];
    }
    while(m --){
        int l, r;
        cin >> l >> r;
        cout << s[r] - s[l - 1] << endl;
    }
    return 0;
}