Cod sursa(job #671299)

Utilizator TIBSTiberiu Iorgulescu 321CA TIBS Data 31 ianuarie 2012 09:37:40
Problema Fractii Scor 30
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.29 kb
Raporteaza aceasta sursa 
#include<fstream>
using namespace std;

int main()
{ifstream f("fractii.in");
int n, i, j, phi[100000], nr=0;
f>>n;
f.close();
for(i=1;i<=n;i++)
	phi[i]=i-1;
for(i=2;i<=n;i++)
	{for(j=2*i;j<=n;j+=i)
		phi[j]-=phi[i];
	nr+=phi[i];
	}
ofstream g("fractii.out");
g<<nr*2+1;
return 0;
}