Cod sursa(job #1241400)

Utilizator george.opritaOprita George george.oprita Data 13 octombrie 2014 15:03:46
Problema Ciurul lui Eratosthenes Scor 90
Compilator cpp Status done
Runda Arhiva educationala Marime 0.32 kb
Raporteaza aceasta sursa 
#include <fstream>
#include <cmath>
using namespace std;
bool a[2000000];
int main()
{
 int n,i,j,nr=0;
 ifstream in ("ciur.in");
 ofstream out ("ciur.out");
 in>>n;
 a[2]=1;
 for(i=3;i<=n;i=i+2)
 a[i]=1;
 for(i=2;i<sqrt(n);i++)
 for(j=i;j<=n/i;j++)
 a[i*j]=0;
 for(i=2;i<=n;i++)
 if(a[i])
 nr++;
 out<<nr;

    return 0;
}