Cod sursa(job #622123)

Utilizator masterchiefSabin Olaru masterchief Data 17 octombrie 2011 14:21:38
Problema Ciurul lui Eratosthenes Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.33 kb
Raporteaza aceasta sursa 
#include <cstdio>
using namespace std;
int n,i,nr = 0;
bool a[2000000];
int main(){
int n;
freopen("ciur.in","r",stdin);
freopen("ciur.out","w",stdout);
scanf("%d",&n);
for(int i=2;i*i<= n;++i)
	if(!a[i])
for (int j=i*i;j<=n;j+=i)
    a[j]=true;
for (int i=2;i<=n;++i)
    if(!a[i])
       nr++;
printf("%d",nr);
return 0;
}