Cod sursa(job #1598958)
Utilizator | Ciocoveanu Alin alinciocoveanu | Data | 13 februarie 2016 14:47:15 |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 20 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.67 kb |
#include <fstream>
using namespace std;
int n;
bool viz[2000005];
void citire()
{
ifstream fin ("ciur.in");
fin>>n;
fin.close();
}
void rezolvare()
{
int p,nrprime=0;
ofstream fout ("ciur.out");
for (int i=2;i<=7;i++)
{
if (viz[i]==0)
{
viz[i]=1;
p=i;
nrprime++;
while (p<=n)
{
p=p+i;
viz[p]=1;
}
}
}
for (int i=11;i<=n;i++)
if (viz[i]==0)
nrprime++;
fout<<nrprime;
fout<<'\n';
fout.close();
}
int main()
{
citire();
rezolvare();
return 0;
}