C++
#include <iostream>
#include <algorithm>
#include <cstring>
using namespace std;
const int N = 1e5 + 10;
int n, m, a[N], s[N];
int main(){
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;
}