Cod sursa(job #978891)

Utilizator raulstoinStoin Raul raulstoin Data 30 iulie 2013 00:50:07
Problema Ciurul lui Eratosthenes Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.35 kb
Raporteaza aceasta sursa 
#include<fstream>

#define NMAX 2000005
using namespace std;

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

bool prim[NMAX];
int n,sol;

int main()
{
	fin>>n;
	for(int i=2;i<=n;i++)
		if(prim[i]^1)
		{
			sol++;
			for(int j=i+i;j<=n;j+=i)
				prim[j]|=1;
		}
	fout<<sol<<'\n';
	
	fin.close();
	fout.close();
	
	return 0;
}