Cod sursa(job #654190)

Utilizator BarracudaFMI-Alex Dobrin Barracuda Data 29 decembrie 2011 20:10:20
Problema Ciurul lui Eratosthenes Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.31 kb
Raporteaza aceasta sursa 
#include<cstdio>
#include<math.h>
#define lim 2000002
long long  n,k,i,j;
bool v[lim];
int main (){
	freopen("ciur.in","r",stdin);
	freopen("ciur.out","w",stdout);
	scanf("%lld",&n);
	for( i=2;i<=n;i++)
		if(!v[i]){
			k++;
			for( j=i+i;j<=n;j+=i)
				v[j]=1;
		}
	printf("%lld",k);
	return 0;
}