Cod sursa(job #278809)
Utilizator | Data | 12 martie 2009 15:33:26 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.34 kb |
#include<fstream>
using namespace std;
ifstream fin("ciur.in");
ofstream fout("ciur.out");
long n,e;
bool p[2000000];
int main()
{ fin>>n;
p[1]=true;
for(long i=1;i<=n;i++)
if(p[i]==false) { e++;
for(long j=i;j<=n;j+=i)
p[j]=true;
}
fout<<e;
fin.close();
fout.close();
return 0;
}