Cod sursa(job #2446974)

Utilizator IoanMihaiIoan Mihai IoanMihai Data 11 august 2019 13:54:33
Problema Fractii Scor 30
Compilator cpp-64 Status done
Runda Arhiva de probleme Marime 0.31 kb
Raporteaza aceasta sursa 
#include<bits/stdc++.h>
using namespace std;
ifstream fin("fractii.in");
ofstream fout("fractii.out");
int n,nr,i,j,v[1000005];
int main()
{
  fin>>n;
  for (i=2;i<=n;i++)
   v[i] = i-1;
  for (i=2;i<=n;i++)
   {
     nr += v[i];
     for (j=i*2;j<=n;j+=i)
      v[j] -= v[i];
   }
  fout<<2*nr+1<<'\n';
  return 0;
}