Cod sursa(job #235761)

Utilizator IAmASuperCerealVictor Andrei IAmASuperCereal Data 25 decembrie 2008 19:45:31
Problema Ciurul lui Eratosthenes Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.33 kb
Raporteaza aceasta sursa 
#include<stdio.h>
int main()
{
	int n,i,j,nr=0;
	bool a[2000001];
	freopen("ciur.in","r",stdin);
	freopen("ciur.out","w",stdout);
	scanf("%d",&n);
	for(i=2;i<=n;i++)
		a[i]=true;
	for(i=2;i*i<=n;i++)
		if(a[i])
			for(j=i*i;j<=n;j=j+i)
				a[j]=false;
	for(i=2;i<=n;i++)
		if(a[i]) nr++;
	printf("%d",nr);
		return 0;
}