Cod sursa(job #2723432)

Utilizator dcovDarius Covaciu dcov Data 14 martie 2021 00:58:07
Problema Ciurul lui Eratosthenes Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.35 kb
Raporteaza aceasta sursa 
#include <bits/stdc++.h>

using namespace std;

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

long long d,i,n,nr;
bool a[2000010];

int main()
{
    for(d=2;d*d<=2000000;d++)
        if(a[d]==0)
            for(i=d*d;i<=2000000;i+=d)
                a[i]=1;

    f>>n;
    for(i=2;i<=n;i++)nr+=(1-a[i]);
    g<<nr;
    return 0;
}