Cod sursa(job #1898570)

Utilizator jason2013Andronache Riccardo jason2013 Data 2 martie 2017 09:37:40
Problema Fractii Scor 100
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.35 kb
Raporteaza aceasta sursa 
#include<bits/stdc++.h>

using namespace std;

ifstream in ("fractii.in");
ofstream out ("fractii.out");

int v[1000001];
int main()
{
  long long s;
  int n;
  s = 1;
  in>>n;
  for(int i = 2 ;i <= n;i++){
    v[i] += i - 1;
    for(int j = (i<<1); j <= n ;j += i)
      v[j]-= v[i];
    s += v[i] * 2;
  }
  out<<s;
  return 0;
}