Cod sursa(job #304884)

Utilizator h_balazsHevele Balazs h_balazs Data 15 aprilie 2009 15:56:26
Problema Fractii Scor 90
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.34 kb
Raporteaza aceasta sursa 
#include<stdio.h>
int main()
{
	freopen("fractii.in","r",stdin);
	freopen("fractii.out","w",stdout);
	long n;
	long a[1000002];
	long long b;
	b=1;
	scanf("%ld",&n);
	for(long i=2;i<=n;i++)
	  {
	  a[i-2]+=i-1;
	  for(long j=2*i;j<=n;j+=i)
	    {
		a[j-2]-=a[i-2];
		}
	  b+=2*a[i-2];
	  }
	 printf("%lld",b);
	 return 0;
}