[백준][Java] 1929번 소수 구하기 (에라토스테네스의 체)

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
 
 
public class Main {
        
    private static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    private static BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
    
    
    
    public static void main(String[] args) throws IOException{
        String[] str = br.readLine().split(" ");
        
        boolean[] prime = new boolean[1000001];
        prime[0] = prime[1] = true;
        
        int A = Integer.parseInt(str[0]);
        int B = Integer.parseInt(str[1]);
        
        for(int i=2; i*i<=B; i++) {
            if(!prime[i]) {
                for(int j=i*i; j<=B; j+=i) {
                    prime[j]=true;
                }
            }        
        }
        for(int i=A; i<=B; i++){
            if(!prime[i]) System.out.println(i);
        }
        
//        bw.write("");
//        bw.flush(); 
//        bw.close();
    }
}