Cod sursa(job #432213)
Utilizator | Data | 1 aprilie 2010 23:00:35 | |
---|---|---|---|
Problema | Fractii | Scor | 10 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.27 kb |
#include<fstream>
using namespace std;
long n,a[1000],i,j,s=0;
int main()
{
ifstream f("fractii.in");
ofstream g("fractii.out");
f>>n;
for(i=2;i<=n;i++)
a[i]=i-1;
for(i=2;i<=n;i++)
{
s=s+a[i];
for(j=i*2;j<=n;j=j+i)
a[j]=a[j]-a[i];
}
s=s*2+1;
g<<s;
return 0;
}