Cod sursa(job #520073)

Utilizator micutuzBalog Adrian micutuz Data 7 ianuarie 2011 13:23:26
Problema Fractii Scor 100
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.36 kb
Raporteaza aceasta sursa 
#include<iostream>
#include<fstream>

using namespace std;
int x[1000000];
int main()
{
	ifstream f("fractii.in");
	ofstream g("fractii.out");
	
	long long n, i, j, k=0;
	
	f>>n;
	
	for(i=1;i<=n;i++)
		x[i]=i-1;
	for(i=2;i<=n;i++)
	{	k=k+x[i];
		for(j=i*2;j<=n;j+=i)
			x[j]-=x[i];
	}
	
	g<<k*2+1;
	
	f.close();
	g.close();
	return 0;
}