Cod sursa(job #1652346)

Utilizator andrew_assassin789Andrei Manea andrew_assassin789 Data 14 martie 2016 21:30:59
Problema Ciurul lui Eratosthenes Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.35 kb
Raporteaza aceasta sursa 
#include <fstream>

using namespace std;
bool c[2000001];
int main()
{
    ifstream f("ciur.in");
    ofstream g("ciur.out");
    unsigned int  n,i,j,nr;
    f>>n;nr=n-1;
    for (i=2;i*i<=n;i++)
    {
        for (j=2*i;j<=n;j+=i)
            if (!c[j]) c[j]=1,nr--;
    }
    g<<nr<<'\n';
    f.close();
    g.close();
    return 0;
}