Cod sursa(job #1665612)
Utilizator | Macovei Octavian-Cosmin Mc_Tavi | Data | 27 martie 2016 10:16:22 |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 30 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.6 kb |
#include <fstream>
using namespace std;
ifstream fin("ciur.in");
ofstream fout("ciur.out");
int n,ciur[2000001],prime,i,d;
/*int prim(int n,int d)
{
if(d==1)
return 1;
else
if(n%d==0)
return 0;
else
return prim(n,d-1);
}*/
int main()
{
fin>>n;
ciur[1]=1;
for(d=2;d<=n/2;d++)
{
if(ciur[d]==0)
{
for(i=2;i*d<=n;i++)
{
ciur[i*d]=1;
}
}
}
for(i=1;i<=n;i++)
if(ciur[i]==0)
prime++;
fout<<prime;
return 0;
}