Cod sursa(job #1460444)

Utilizator valentin50517Vozian Valentin valentin50517 Data 12 iulie 2015 18:20:54
Problema Ciurul lui Eratosthenes Scor 70
Compilator cpp Status done
Runda Arhiva educationala Marime 0.31 kb
Raporteaza aceasta sursa 
#include <fstream>

using namespace std;
ifstream fin("ciur.in");
ofstream fout("ciur.out");

int N;
bool A[2000001];

int gen_ciur(){
	int i,j,rs = 1;
	for(i=2;i<=N;i++){
		for(j=i*2;j<=N;j+=i) if(!A[j]) rs++,A[j] = 1;
	}
	return rs;
}
int main(){
	fin >> N;
	fout << N-gen_ciur();
	return 0;
}