Cod sursa(job #304878)

Utilizator h_balazsHevele Balazs h_balazs Data 15 aprilie 2009 15:40:03
Problema Fractii Scor 30
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.33 kb
Raporteaza aceasta sursa 
#include<stdio.h>
int main()
{
	freopen("fractii.in","r",stdin);
	freopen("fractii.out","w",stdout);
	long n;
	long a[1000001];
	long long b;
	a[1]=0;
	b=1;
	scanf("%ld",&n);
	for(int i=2;i<=n;i++)
	  {
	  a[i]+=i-1;
	  for(int j=2*i;j<=n;j+=i)
	    {
		a[j]-=a[i];
		}
	  b+=2*a[i];
	  }
	 printf("%ld",b);
	 return 0;
}