Cod sursa(job #272909)

Utilizator PopaStefanPopa Stefan PopaStefan Data 7 martie 2009 22:26:31
Problema Ciurul lui Eratosthenes Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 0.35 kb
Raporteaza aceasta sursa 
#include<fstream.h>
#include<math.h>

ifstream fin("ciur.in");
ofstream fout("ciur.out");

int ciur[2000001];
long long int n;

int main()
{int i,j,nr=0;
fin>>n;
for(i=2;i<=sqrt(n);i++)
   if(ciur[i]==0)
   for(j=2;i*j<=n;j++)
	  ciur[i*j]=1;
for(i=2;i<=n;i++)
   if(ciur[i]==0) nr++;
fout<<nr;
fin.close();
fout.close();
return 0;
}