Cod sursa(job #633733)

Utilizator WuximUrsinschi Eduard Wuxim Data 14 noiembrie 2011 17:50:02
Problema Ciurul lui Eratosthenes Scor 60
Compilator cpp Status done
Runda Arhiva educationala Marime 0.35 kb
Raporteaza aceasta sursa 
#include <fstream>

using namespace std;

ifstream f("ciur.in");
ofstream g("ciur.out");

char v[2000001];
long x,nr,k,n;
int main()
{  f>>n;
   for(x=1;x<=n;x++)v[x]=1;
   nr=0;
   for(x=2;x<=n;x++)
      if(v[x]){ nr++;
                for(k=x+x;k<=n;k=k+x)v[k]=0;
              }
  g<<nr<<'\n';
  f.close();g.close();
  return 0;
}