Cod sursa(job #463530)

Utilizator alisssiaMititelu Andra alisssia Data 16 iunie 2010 12:36:50
Problema Ciurul lui Eratosthenes Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.34 kb
Raporteaza aceasta sursa 
using namespace std;
#include<cstdio>
#define nmax 2000001
unsigned int n,i,j;
bool a[nmax];

int main()
{
	freopen("ciur.in","r",stdin);
	freopen("ciur.out","w",stdout);
	scanf("%d",&n);
	for(i=2;i<=n;i++)
		if(!a[i])
			for(j=2*i;j<=n;j=j+i) a[j]=true;
	j=0;
	for(i=2;i<=n;i++)
		if(!a[i]) j++;
	printf("%d\n",j);
		return 0;
}