Cod sursa(job #520076)

Utilizator raduiris94Alexa Radu raduiris94 Data 7 ianuarie 2011 13:24:19
Problema Fractii Scor 100
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.31 kb
Raporteaza aceasta sursa 
#include<iostream>
#include<fstream>
using namespace std;
ifstream f("fractii.in");
ofstream g("fractii.out");
long long rez, n, i, j, a[1000002];
int main()
{
	f>>n;
	for(i=2; i<=n; i++)
		a[i]=i-1;
	for(i=2; i<=n; i++)
	{
		rez=rez+a[i];
		for(j=i*2; j<=n; j=j+i)
			a[j]=a[j]-a[i];
	}
	g<<2*rez+1;
}