Cod sursa(job #531222)

Utilizator belicosuspusherino TALENT belicosus Data 9 februarie 2011 10:59:56
Problema Ciurul lui Eratosthenes Scor 90
Compilator cpp Status done
Runda Arhiva educationala Marime 0.29 kb
Raporteaza aceasta sursa 
#include<fstream>
using namespace std;
ifstream in("ciur.in");
ofstream out("ciur.out");
int main()
{
	int n,i,j,p=0;
	bool c[2000005];
	in>>n;
	for(i=2;i*i<=n;i++)
		if(c[i]==false)
			for(j=i*i;j<n;j+=i)
				c[j]=true;
	for(i=2;i<n;i++)
		if(c[i]==false)
			p++;
	out<<p;
}