[JAVA] 프로그래머스 - 햄버거 만들기

<출처>

프로그래머스 코딩 테스트 연습, https://school.programmers.co.kr/learn/challenges

https://school.programmers.co.kr/learn/courses/30/lessons/133502

프로그래머스

 

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<해결 방법 1>

ArrayList 사용하여 단순 반

public static int solution(int[] ingredient) {
    int answer = 0;

    int[] burger = new int[]{1, 2, 3, 1};
    ArrayList<Integer> checkList = new ArrayList<>();

    for (int i = 0; i < ingredient.length; i++) {
        checkList.add(ingredient[i]);

        if (checkList.size() >= 4) {
            int[] temp = new int[4];
            temp[0] = checkList.get(checkList.size() - 4);
            temp[1] = checkList.get(checkList.size() - 3);
            temp[2] = checkList.get(checkList.size() - 2);
            temp[3] = checkList.get(checkList.size() - 1);

            if (Arrays.equals(temp, burger)) {
                answer++;
                checkList.remove(checkList.size() - 1);
                checkList.remove(checkList.size() - 1);
                checkList.remove(checkList.size() - 1);
                checkList.remove(checkList.size() - 1);
            }
        }
    }

    return answer;
}

 

 

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<해결 방법 2>

public static int solution2(int[] ingredient) {
    int answer = 0;

    Stack<Integer> checkList = new Stack<>();
    int[] burger = new int[]{1, 3, 2, 1};

    for (int i = 0; i < ingredient.length; i++) {
        checkList.push(ingredient[i]);

        if (checkList.size() >= 4) {
            ArrayList<Integer> temp = new ArrayList<>();

            for(int p=0; p<4; p++) {
                if(checkList.peek() != burger[p]){
                    break;
                }
                temp.add(checkList.pop());
            }

            if(temp.size()==4){
                answer++;
            }
            else {
                for(int j=temp.size()-1; j>=0; j--){
                    checkList.push(temp.get(j));
                }
            }
        }
    }

    return answer;
}