Cod sursa(job #527117)

Utilizator Eugen01Vasilescu Eugen Eugen01 Data 30 ianuarie 2011 17:05:23
Problema Ciurul lui Eratosthenes Scor 30
Compilator cpp Status done
Runda Arhiva educationala Marime 0.34 kb
Raporteaza aceasta sursa 
#include<stdio.h>

int i,j,n,m;
char a[2000001];

int ciur(int n)
{
	int nr=0;
	for (i=2;i<=n;i++)
		for (j=2*i;j<=n;j+=i)
			a[j]=1;
	
	for (i=2;i<=n;i++)
		if (!a[i]) nr++;
	return nr;
}

int main()
{
	freopen("ciur.in","r",stdin);
	freopen("ciur.out","w",stdout);
	
	scanf("%d",&n);
	
	printf("%d\n",ciur(n));
	return 0;
}