Cod sursa(job #662263)

Utilizator Stefex09Stefan Teodorescu Stefex09 Data 16 ianuarie 2012 12:01:39
Problema Fractii Scor 100
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.33 kb
Raporteaza aceasta sursa 
#include<cstdio>
#define MAX 1000001
using namespace std;
long v[MAX];
int main()
{
	freopen("fractii.in","r",stdin);
	freopen("fractii.out","w",stdout);
	long long i,j,n,nr=0;
	scanf("%lld",&n);
	for(i=2;i<=n;i++) v[i]=i-1;
	for(i=2;i<=n;i++) 
	{
		for(j=i+i;j<=n;j+=i)
			v[j]-=v[i];
		nr+=v[i];
	}
	nr=nr*2+1;
	printf("%lld",nr);
}