Cod sursa(job #403836)
Utilizator | Data | 25 februarie 2010 13:50:46 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 0 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.33 kb |
#include<fstream>
#define NM 2000000
using namespace std;
int main()
{
ifstream fin("ciur.in");
ofstream fout("ciur.out");
char v[NM+1]={0};
int i,j,n;
fin>>n;
v[1]=1;
for(i=2;i<=n/2;i++)
if(!v[i])
for(j=2;j*i<n;j++)
v[i*j]=1;
int x=0;
for(i=2;i<=n;i++)
if(!v[i])x++;
fout<<x;
return 0;
}