240319 n + 1 카드게임

private static int numberOfCards;

public int solution(int initialCoins, int[] cards) {
	numberOfCards = cards.length;

	boolean[] hand = new boolean[numberOfCards + 1];
	boolean[] paid = new boolean[numberOfCards + 1];
	int coinsLeft = initialCoins;

	for (int i = 0; i < numberOfCards / 3; i++) {
		hand[cards[i]] = true;
		paid[cards[i]] = true;
	}

	int answer = 1;
	for (int i = numberOfCards / 3; i < numberOfCards; i += 2) {
		if (coinsLeft > 0) {
			hand[cards[i]] = true;
			hand[cards[i + 1]] = true;
		}

		boolean pass = false;
		int minCost = 3;
		int cardThrown = -1;

		for (int j = 1; j <= numberOfCards; j++) {
			if (!hand[j]) {
				continue;
			}

			if (hand[numberOfCards + 1 - j]) {
				int cost = (paid[j] ? 0 : 1) + (paid[numberOfCards + 1 - j] ? 0 : 1);
				if (coinsLeft < cost || minCost <= cost) {
					continue;
				}

				pass = true;
				cardThrown = j;
				minCost = cost;
			}
		}

		if (!pass) {
			break;
		}

		hand[cardThrown] = false;
		hand[numberOfCards + 1 - cardThrown] = false;
		coinsLeft -= minCost;

		answer++;
	}

	return answer;
}

출처:https://school.programmers.co.kr/learn/courses/30/lessons/258707