Cod sursa(job #1040468)

Utilizator vlad233Dragan Vlad vlad233 Data 24 noiembrie 2013 15:56:39
Problema Ciurul lui Eratosthenes Scor 30
Compilator cpp Status done
Runda Arhiva educationala Marime 0.36 kb
Raporteaza aceasta sursa 
#include <iostream>
#include <fstream>

using namespace std;

int main()
{
	int n,i,j,nr=1,a[2000002];
	ifstream f("ciur.in");
	f>>n;
	f.close();
	for (i=3;i<=n;i+=2)
		a[i]=1;
	for (i=3;i<=n;i+=2)
	{
		if (a[i]==1)
		{
			nr++;
			for (j=3*i;j<=n;j+=2*i)
				a[j]=0;
		}
	}
	ofstream g("ciur.out");
	g<<nr;
	g.close();
	return 0;
}