20. 나누어 떨어지는 숫자 배열 (Array, List, ArrayList)

import java.util.List;
import java.util.ArrayList;

class Solution {
    public int[] solution(int[] arr, int divisor) {
        int[] answer = {};
        List<Integer> list = new ArrayList<Integer>();
        for(int i = 0; i < arr.length ; i++) {
            if(arr[i] % divisor == 0){
                list.add(arr[i]);
            }
        }
        if(list.isEmpty()){
            list.add(-1);
        }else {
            list.sort(null);
        }                
        answer = new int[list.size()];
        for(int i = 0; i < list.size() ; i++) {
            answer[i] = list.get(i);
        }
        return answer;
    }
}

 

list.isEmpty()