230413 혼자 놀기의 달인

public int solution(int[] cards) {
    int[] max = { 0, 0 };

    for (int i = 0; i < cards.length; i++) {
        if (cards[i] == -1) {
            continue;
        }
        int circleSize = getCircuitSize(cards, i);
        if (max[0] < circleSize) {
            max[1] = max[0];
            max[0] = circleSize;
        } else if (max[1] < circleSize) {
            max[1] = circleSize;
        }
        if (max[0] == cards.length)
            return 0;
    }

    return max[0] * max[1];
}

private int getCircuitSize(int[] cards, int index) {
    if (cards[index] == -1) {
        return 0;
    }
    int nextIndex = cards[index] - 1;
    cards[index] = -1;
    return getCircuitSize(cards, nextIndex) + 1;
}

출처:https://school.programmers.co.kr/learn/courses/30/lessons/131130