Cod sursa(job #1988487)

Utilizator adriananicolaeAdriana Nicolae adriananicolae Data 3 iunie 2017 10:15:47
Problema Ciurul lui Eratosthenes Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 0.51 kb
#include <bits/stdc++.h>
using namespace std;
ifstream fin("ciur.in");ofstream fout("ciur.out");


int main()
{   const int Nmax=1000001;
    bitset<Nmax>ciur;
    ciur[1]=1;
    for(int i=4;i<=Nmax;i+=2)
        ciur[i]=1;
    for(int i=3;i*i<=Nmax;i+=2){
        if(ciur[i]==0)
            for(int j=i*i;j<=Nmax;j=j+2*i){
                ciur[j]=1;
            }
    }
    int n,a,cnt=0;
    fin>>n;for(int i=0;i<n;i++){
        fin>>a;if(ciur[a]==0)cnt++;
    }
    fout<<cnt;
    return 0;
}