Cod sursa(job #383555)
Utilizator | Data | 16 ianuarie 2010 20:51:59 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.27 kb |
#include <fstream>
using namespace std;
ifstream f("ciur.in");
ofstream g("ciur.out");
char a[2000001];
int n,i,j,nr;
int main()
{
f>>n;nr=0;
for (i=2;i<=n;i++)
{ if (a[i]==0)
{nr++;
for (j=2;j<=n/i;j++)
a[i*j]=1;
}
}
g<<nr;
g.close();
return 0;
}