Cod sursa(job #1461658)

Utilizator Ruben2015Parvu Ruben Ruben2015 Data 16 iulie 2015 10:26:05
Problema Ciurul lui Eratosthenes Scor 30
Compilator cpp Status done
Runda Arhiva educationala Marime 0.36 kb
Raporteaza aceasta sursa 
#include <iostream>
#include <fstream>
using namespace std;
ifstream f("ciur.in");
ofstream g ("ciur.out");
int a[2000000],n,i,x,j;
int main()
{ f>>n;
    for(i=2;i*i<=n;i++)
{
    if(a[i]==0)
    {
        for(x=i*2;x<=n;x=x+i)
        a[x]=3;
    }
}
for(i=2;i<=n;i++)
{
    if(a[i]==0)
    {
        j++;
    }
}
g<<j;
    return 0;
}