[알고리즘문제풀기] 왼쪽 오른쪽

문제

내가 작성한 정답

ArrayList

import java.util.ArrayList;

class Solution {
    public String[] solution(String[] str_list) {
        ArrayList<String> answer = new ArrayList<>();
        for(int i=0; i<str_list.length; i++){
            if(str_list[i].equals("l")) {
                for(int j=0; j<i; j++){
                    answer.add(str_list[j]);
                }
                break;
            } else if (str_list[i].equals("r")) {
                for(int j=i+1; j<str_list.length; j++){
                    answer.add(str_list[j]);
                }
                break;
            }
        }
        return answer.toArray(String[]::new);
    }
}

Arrays.copyOfRange

import java.util.Arrays;

class Solution {
    public String[] solution(String[] str_list) {
        String[] answer = new String[0];
        for(int i=0; i<str_list.length; i++){
            if(str_list[i].equals("l")){
                answer = Arrays.copyOfRange(str_list,0,i);
                break;
            } else if (str_list[i].equals("r")) {
                answer = Arrays.copyOfRange(str_list,i+1,str_list.length);
                break;
            }
        }
        return answer;
    }

다른 사람들의 정답

Arrays.copyOfRange

import java.util.Arrays;

class Solution {
    public String[] solution(String[] str_list) {

        for (int i = 0; i < str_list.length; i++) {

            if ("l".equals(str_list[i])) {
                return Arrays.copyOfRange(str_list, 0, i);
            } else if ("r".equals(str_list[i])) {
                return Arrays.copyOfRange(str_list, i + 1, str_list.length);
            }
        }

        return new String[0];
    }

stream

import java.util.Arrays;
import java.util.stream.IntStream;

class Solution {
    public String[] solution(String[] str_list) {
        return IntStream.range(0, str_list.length)
                .boxed()
                .filter(i -> str_list[i].equals("l") || str_list[i].equals("r"))
                .findFirst()
                .map(i -> {
                    if (str_list[i].equals("l")) {
                        return Arrays.copyOfRange(str_list, 0, i);
                    }
                    return Arrays.copyOfRange(str_list, i + 1, str_list.length);
                })
                .orElseGet(() -> new String[]{});
    }
}