Cod sursa(job #668050)

Utilizator firewavesBirsu Ion firewaves Data 24 ianuarie 2012 11:01:31
Problema Fractii Scor 100
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.33 kb
Raporteaza aceasta sursa 
#include <fstream>
using namespace std;
ifstream h("fractii.in");
ofstream g("fractii.out");
long a[1000001];
long long i,j,n,nr=0;
int main()
{  h>>n;
   for(i=2;i<=n;i++) a[i]=i-1;
     for(i=2;i<=n;i++) {
       for(j=i+i;j<=n;j+=i)
         a[j]-=a[i];
     nr+=a[i];}
    nr=nr*2+1;
    g<<nr;
    h.close();g.close();
    return 0;
}