testprefixsum.cpp

#include <iostream>
using namespace std;
const int N = 1e5+10;
int a[N];
int pf[N];
 
int main() {
  int n;
  cin >> n;
  for(int i=0; i<n; i++){
    cin >> a[i];
    pf[i] = pf[i-1] + a[i];
  }
  int q;
  cin >> q;
  while(q--){
    int l, r;
    cin >> l >> r;
  //Calculating sum from r to l.
    cout << pf[r] - pf[l-1] << endl;
     
  }
   return 0;
}