Cod sursa(job #1311464)

Utilizator RaulBodrogeanMircea-Raul Bodrogean RaulBodrogean Data 8 ianuarie 2015 11:29:44
Problema Ciurul lui Eratosthenes Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.32 kb
Raporteaza aceasta sursa 
#include <fstream>
using namespace std;
ifstream in ("ciur.in");
ofstream out ("ciur.out");
int main() {
bool a[2000001];
int nr=0, n, i, j;
in>>n;
for (i=2;i<=n;i++)
  a[i]=1;
for (i=2;i<=n/2;i++)
 if (a[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;
}