题解

#include <bits/stdc++.h>
using namespace std;
int x[1000005];
int main(){
    int n,m,l,r;
    cin >> n >> m;
    for(int i = 1;i <= n;i++){
    	cin >> x[i];
        x[i] += x[i-1];
    }
    while(m--){
    	cin >> l >> r;
        cout << x[r] - x[l - 1] << endl;
    }
    return 0;
}