Cod sursa(job #444932)

Utilizator ClasianMunteanu Petre Clasian Data 22 aprilie 2010 09:35:25
Problema Ciurul lui Eratosthenes Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.3 kb
Raporteaza aceasta sursa 
#include<fstream>
using namespace std;
ifstream f("ciur.in");
ofstream g("ciur.out");
int n,i,j,nr;
char v[2000001];
int main()
{ f>>n;
  for(i=2;i<=n;i++)v[i]=1;
  for(i=2;i<=n;i++)if(v[i])
  {
	  nr++;
	  for(j=i<<1;j<=n;j+=i)v[j]=0;
  }
  g<<nr;
  f.close();
  g.close();
  return 0;
}