Cod sursa(job #284731)

Utilizator mathboyDragos-Alin Rotaru mathboy Data 21 martie 2009 22:15:31
Problema Fractii Scor 100
Compilator cpp Status done
Runda petru_toti Marime 0.29 kb
Raporteaza aceasta sursa 
#include <fstream.h>
ifstream f("fractii.in");
ofstream g("fractii.out");
int main()
{
long long v[1000001],i,n,j,s=0;
f>>n;
for(i=2;i<=n;i++) v[i]=i;
for(i=2;i<=n;i++)
	{ if(v[i]==i) for(j=i;j<=n;j=j+i)
		       	v[j]=v[j]/i*(i-1); }
for(i=2;i<=n;i++) s=s+v[i];
g<<2*s+1;
return 0;
}