Cod sursa(job #280472)

Utilizator v14dVlad Baesu v14d Data 13 martie 2009 13:28:38
Problema Fractii Scor 30
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.3 kb
Raporteaza aceasta sursa 
#include<fstream>

using namespace std;
 
long n,v[1000000],nr;

int main()
{ long i,j;
  ifstream fi("fractii.in");ofstream fo("fractii.out");
  fi>>n;
  for(i=1;i<=n;i++) v[i]=i-1;
  for(i=1;i<=n;i++) 
   { for(j=2*i;j<=n;j+=i) v[j]-=v[i]; nr+=v[i];
   }
  fo<<2*nr+1;
  fo.close();fi.close();
return 0;
}