Cod sursa(job #387776)

Utilizator joli94Apostol Adrian Alexandru joli94 Data 28 ianuarie 2010 12:44:48
Problema Ciurul lui Eratosthenes Scor 100
Compilator cpp Status done
Runda concurs_y Marime 0.31 kb
Raporteaza aceasta sursa 
#include<cstdio>

int n,c;
char a[2000005];

int main()
{
	freopen("ciur.in","r",stdin);
	freopen("ciur.out","w",stdout);
	
	int j,i;
	
	scanf("%d",&n);
	for(i=2;i<=n;i++)
		a[i]=1;
	for(i=2;i<=n;i++)
		if(a[i])
		{
			c++;
			for(j=i+i;j<=n;j+=i)
				a[j]=0;
		}
	printf("%d\n",c);
	return 0;
}