Cod sursa(job #278794)
Utilizator | Data | 12 martie 2009 15:26:33 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 30 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.33 kb |
#include<fstream>
using namespace std;
ifstream fin("ciur.in");
ofstream fout("ciur.out");
long n,p[200000],e;
int main()
{ fin>>n;
p[1]=1;
for(long i=1;i<=n;i++)
if(p[i]==0) { e++;
for(long j=i;j<=n;j+=i)
p[j]=1;
}
fout<<e;
fin.close();
fout.close();
return 0;
}