Cod sursa(job #1158763)

Utilizator nickulNic Kul nickul Data 29 martie 2014 02:52:17
Problema Ciurul lui Eratosthenes Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.35 kb
Raporteaza aceasta sursa 
#include<fstream>
#include<vector>

using namespace std;

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

int main()
{
	vector<bool> sol;
	int n,i,j,nr=1;
	in>>n;
	for(i=0;2*i+1<=n;i++)
		sol.push_back(1);
	for(i=1;2*i+1<=n;i++)
		if(sol.at(i))
		{
			nr++;
			for(j=(6*i+3)/2;2*j+1<=n;j+=2*i+1)
				sol.at(j)=0;
		}
	out<<nr;
}