[알고리즘문제풀기] 배열의 원소 삭제하기

문제

내가 작성한 정답

import java.util.ArrayList;

class Solution {
    public int[] solution(int[] arr, int[] delete_list) {
        ArrayList<Integer> answer = new ArrayList<>();
        ArrayList<Integer> del = new ArrayList<>();
        for(int i:delete_list) {
            del.add(i);
        }
        for (int i : arr) {
            if(!del.contains(i)) answer.add(i);
        }
        return answer.stream().mapToInt(a -> a).toArray();
    }
}

다른 사람들의 정답

import java.util.stream.IntStream;

class Solution {
    public int[] solution(int[] arr, int[] delete_list) {
        return IntStream.of(arr).filter(i -> !IntStream.of(delete_list).anyMatch(s -> s == i)).toArray();
    }
}

import java.util.*;
class Solution {
    public int[] solution(int[] arr, int[] delete_list) {
        List<Integer> list = new ArrayList<>();
        for(int n : arr) {
            list.add(n);
        }
        for(int n: delete_list) {
            list.remove((Integer)n);
        }
        int[] answer = new int[list.size()];
        for(int i=0; i<list.size(); i++){
            answer[i] = list.get(i);
        }
        return answer;
    }
}

import java.util.*;

class Solution {
    public int[] solution(int[] arr, int[] delete_list) {
        ArrayList<Integer> arrayList = new ArrayList<>();
        for (int a : arr) 
            if (!isExist(delete_list, a))
                arrayList.add(a);

        int idx = 0;
        int[] answer = new int[arrayList.size()];
        for (int data : arrayList)
            answer[idx++] = data;
        return answer;
    }

    public boolean isExist(int[] arr, int data) {
        for (int a : arr)
            if (a == data)
                return true;
        return false;
    }
}