Cod sursa(job #883205)

Utilizator drobertDumitru Robert drobert Data 19 februarie 2013 20:21:36
Problema Fractii Scor 100
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.33 kb
Raporteaza aceasta sursa 
#include <iostream>
#include <fstream>
using namespace std;
ifstream f("fractii.in");
ofstream g("fractii.out");
long long n,i,j,v[1000005],s;
int main ()
{
	f>>n;
	for (i=1;i<=n;i++)
		v[i]=i;
	for (i=2;i<=n;i++)
		if (v[i]==i)
			for (j=i;j<=n;j+=i)
				v[j]=v[j]/i*(i-1);
	for (i=2;i<=n;i++)
		s+=v[i];
	g<<s*2+1;
}