Cod sursa(job #2104520)

Utilizator epermesterNagy Edward epermester Data 11 ianuarie 2018 19:39:04
Problema Ciurul lui Eratosthenes Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.31 kb
Raporteaza aceasta sursa 
#include<fstream>
using namespace std;

bool numbers[2000000];

int main() {
	ifstream in("ciur.in");
	ofstream out("ciur.out");
	int N;
	in >> N;
	int s = 0;
	for (int i = 2;i <= N;++i)
		if (!numbers[i]) {
			s++;
			for (int j = i; i<1415 && i*j <= N;++j)
				numbers[i*j] = true;
		}
	out << s;
}