231226 할인 행사

public int solution(String[] want, int[] number, String[] discount) {
	int answer = 0;
	Map<String, Integer> matchMap = createMatchMap(want);

	int total = calculateTotal(number);
	int ptr1 = 0;
	int ptr2 = total - 1;

	int[] saleNum = calculateSaleNum(discount, matchMap, total, number);
	while (true) {
		if (checkMatch(number, saleNum))
			answer++;

		if (matchMap.containsKey(discount[ptr1])) {
			saleNum[matchMap.get(discount[ptr1])]--;
		}

		ptr1++;
		ptr2++;

		if (ptr2 == discount.length)
			break;

		if (matchMap.containsKey(discount[ptr2])) {
			saleNum[matchMap.get(discount[ptr2])]++;
		}
	}
	return answer;
}

private Map<String, Integer> createMatchMap(String[] want) {
	Map<String, Integer> matchMap = new HashMap<>();
	for (int i = 0; i < want.length; i++) {
		matchMap.put(want[i], i);
	}
	return matchMap;
}

private int calculateTotal(int[] number) {
	int total = 0;
	for (int i = 0; i < number.length; i++) {
		total += number[i];
	}
	return total;
}

private int[] calculateSaleNum(String[] discount, Map<String, Integer> matchMap, int total, int[] number) {
	int[] saleNum = new int[number.length];
	for (int i = 0; i < total; i++) {
		if (matchMap.containsKey(discount[i])) {
			saleNum[matchMap.get(discount[i])]++;
		}
	}
	return saleNum;
}

private boolean checkMatch(int[] number, int[] saleNum) {
	for (int i = 0; i < number.length; i++) {
		if (number[i] > saleNum[i])
			return false;
	}
	return true;
}

출처:https://school.programmers.co.kr/learn/courses/30/lessons/131127