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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3.  
  4. int main() {
  5.     int n;
  6.     cin >> n;
  7.  
  8.     long long sum = n*(n+1)/2;
  9.     long long f = 1;
  10.     while(f <= n) {
  11.         sum -= 2*f;
  12.         f *= 2;
  13.     }
  14.  
  15.     cout << sum << endl;
  16. }
Success #stdin #stdout 0.01s 5316KB
comments (?)
stdin 
15
stdout 
90
https://ideone.com/ofd5wg
language:
C++14 (gcc 8.3)
created:
1 day ago
visibility:
public

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