Cod sursa(job #272600)
Utilizator | balint andrei andrei_balint | Data | 7 martie 2009 14:55:06 |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 20 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.45 kb |
#include <fstream>
using namespace std;
ifstream cin("ciur.in");
ofstream cout("ciur.out");
int div(int n)
{
int u,x,p,i,j;
char c[2000001]={0};
u=n-1;
for(i=2;i<=n;i++)
c[i-1]=i;
for(p=1;c[p]*c[p]<=n;p++)
{
for(i=p+1;i<=u;i++)
if(c[i]%c[p]==0)
{
u=u-1;
x=i;
for(j=x;j<=n;j++)
c[j]=c[j+1];
}
}
cout<<u;
return 0;
}
int main()
{
int n;
cin>>n;
div(n);
cin>>n;
return 0;
}