Cod sursa(job #269082)

Utilizator Cristy94Buleandra Cristian Cristy94 Data 2 martie 2009 13:05:17
Problema Fractii Scor 100
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.27 kb
Raporteaza aceasta sursa 
#include<fstream.h>
ifstream f("fractii.in");
ofstream g("fractii.out");
long long a[1000001],n,s,i,j;
int main(){
f>>n;
for(i=1;i<=n;i++)
   a[i]=i-1;
s=0;
for(i=1;i<=n;i++){
   for(j=2*i;j<=n;j=j+i)
       a[j]=a[j]-a[i];
   s=s+a[i];
   }
g<<2*s+1;
return 0;
}