Cod sursa(job #2011582)

Utilizator TudorFinaruTudor Cristian Finaru TudorFinaru Data 16 august 2017 17:02:35
Problema Ciurul lui Eratosthenes Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.32 kb
Raporteaza aceasta sursa 
#include <fstream>
using namespace std;
ifstream f("ciur.in");
ofstream g("ciur.out");
int n,nr,i,j;
bool ciur[2000005];
int main()
{
    f>>n;
    for(i=2;i<=n/2;i++)
        if(ciur[i]==0)
            for(j=i+i;j<=n;j+=i)
                ciur[j]=1;
    for(i=2;i<=n;i++) if(!ciur[i]) nr++;
    g<<nr<<'\n';
}