Cod sursa(job #550302)

Utilizator alyn_acalin alin alyn_ac Data 9 martie 2011 12:49:26
Problema Ciurul lui Eratosthenes Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.31 kb
Raporteaza aceasta sursa 
#include<fstream.h>
bool v[2000001];
int i,j,n,p;
int main()
{
	ifstream fin("ciur.in");
	ofstream fout("ciur.out");
	fin>>n;
	for(i=2;i<=n;i++)
	{
		if(!v[i])
			for(j=i+i;j<=n;j+=i)
				v[j]=true;
	}
	for(i=2;i<=n;i++)
		if(!v[i])
			p++;
	fout<<p;
	fin.close();
	fout.close();
	return 0;
}