Cod sursa(job #671188)
Utilizator | UBB Bora Dan DaNutZ2UuU | Data | 30 ianuarie 2012 21:41:14 |
---|---|---|---|
Problema | Fractii | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.41 kb |
#include <fstream>
using namespace std;
ifstream fin("fractii.in");
ofstream fout("fractii.out");
long a[1000000];
long long i,j,k,n,nr=0;
int main()// int k;
{ fin>>n;
// for(k=1;k<=n;k++)
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;
fout<<nr;
fin.close();
fout.close();
return 0;
}