Cod sursa(job #2332991)

Utilizator PaulRPFRebenciuc Paul-Florin PaulRPF Data 31 ianuarie 2019 16:02:52
Problema Ciurul lui Eratosthenes Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.33 kb
Raporteaza aceasta sursa 
#include <bits/stdc++.h>
using namespace std;
ifstream f("ciur.in");
ofstream g("ciur.out");
bitset <2000002>a;
int i,j,nr=1,k,N;
void Ciur()
{
    for(i=3;i*i<=N;i++)
    if(a[i]==0)
    for(j=i*i;j<=N;j+=i)a[j]=1;

    for(i=3;i<=N;i+=2)nr+=(a[i]==0);
}
int main()
{
    f>>N;
    Ciur();g<<nr;
    return 0;
}