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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3. typedef long long ll;
  4.  
  5. const int MAXN = 1e6 + 5;
  6.  
  7. int n, q;
  8. vector<ll> a(MAXN, 0);
  9. vector<ll> Prefix(MAXN, 0);
  10. vector<ll> Square(MAXN, 0);
  11.  
  12. void fastip() {
  13.     ios_base::sync_with_stdio(0);
  14.     cin.tie(0); cout.tie(0);
  15. }
  16.  
  17. int main() {
  18.     fastip();
  19.     cin >> n >> q;
  20.     for (int i = 1; i <= n; i++) {
  21.         cin >> a[i];
  22.         Prefix[i] = Prefix[i-1] + a[i];
  23.         Square[i] = Square[i-1] + 1ll * a[i] * a[i];
  24.     }
  25.  
  26.     while (q--) {
  27.         int u, v;
  28.         cin >> u >> v;
  29.         ll S = Prefix[v] - Prefix[u-1];
  30.         ll Sq = Square[v] - Square[u-1];
  31.         ll ans = (S * S - Sq) / 2;
  32.         cout << ans << '\n';
  33.     }
  34.     return 0;
  35. }
Success #stdin #stdout 0.01s 26448KB
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stdin 
Standard input is empty
stdout 
Standard output is empty
https://ideone.com/lfMU4g
language:
C++ (gcc 8.3)
created:
16 days ago
visibility:
public

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