Cod sursa(job #199413)

Utilizator LuxOccultaRadu Dolea LuxOcculta Data 18 iulie 2008 17:15:47
Problema Ciurul lui Eratosthenes Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.32 kb
Raporteaza aceasta sursa 
using namespace std;

#include <iostream>
#include <fstream>

const int N=2000005;
bool c[N];

int main(){
	ifstream f("ciur.in");
	ofstream g("ciur.out");
	int nr=0,i,n,j;
	f>>n;
	c[0]=c[1]=true;
	for(i=2;i<=n;++i)
		if(!c[i]){
			for(j=i+i;j<=n;j+=i)
				c[j]=true;
			++nr;
		}
	g<<nr<<endl;
	return 0;
}