백준알고리즘 6359번 만취한 상범

백준알고리즘

https://www.acmicpc.net/problem/6359

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scan = new Scanner (System.in);
        int testCase = Integer.parseInt(scan.nextLine().trim());
        
        for(int ci=0; ci < testCase; ci++) {
            int doorCount = Integer.parseInt(scan.nextLine().trim());
            boolean doorArray[] = new boolean[doorCount + 1];   
            
            for(int i=2; i< doorArray.length; i++) {
                int maxIndex = doorCount / i;
                
                for(int j=1; j <= maxIndex; j++) {
                    if(doorArray[i*j] == true) doorArray[i*j] = false;
                    else doorArray[i*j] = true;
                }
            }
            
            int result = 0;
            for(int i=1; i < doorArray.length; i++) {
                if(!doorArray[i]) result++;
            }
            
            System.out.println(result);
        }        
        scan.close();
    }
}