Cod sursa(job #697337)

Utilizator gabrielvGabriel Vanca gabrielv Data 29 februarie 2012 02:15:51
Problema Ciurul lui Eratosthenes Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.33 kb
Raporteaza aceasta sursa 
using namespace std;
#include<cstdio>
#include<bitset>
#define MAX 2000005
bitset <MAX> ciur;
int n,i,j,c;
int main()
{
	freopen("ciur.in","r",stdin);
	freopen("ciur.out","w",stdout);
	scanf("%d",&n);
	for(i=3;i<=n;i=i+2)
		if(!ciur[i]) 
		{
			c++;
			for(j=i+i+i;j<=n;j=j+i+i)
				ciur[j]=1;
		}
	printf("%d",c+1);
	return 0;
}