？不是我请问呢

测试点强度太高了，看不懂啊

#include <iostream>
#include <cstdio>
using namespace std;
int a[100005];
int main(){
	int n, m, l, r;
    cin >> n >> m;
	for(int i = 1; i <= n; i++){
        cin >> a[i];
	}
    while(m--){
        cin >> l >> r;
        int ct = 0;
        for(int i = l; i <= r; i++){
            ct += a[i];
        }
        cout << ct << endl;
    }

	return 0;
}