#leetcode簽到
Day 4
860. Lemonade Change
恩 Easy
會有人來買檸檬水 檸檬水5元 客人會帶 5 10 20元來買
你要看手上收到的錢可不可以找給所有客人

class Solution:
    def lemonadeChange(self, bills: List[int]) -> bool:
        d = {5: 0, 10: 0, 20: 0}

        for i in bills:
            if i == 5:
                d[i] += 1
            if i == 10:
                if d[5] > 0:
                    d[5] -= 1
                    d[i] += 1
                else:
                    return False
            if i == 20:
                if d[10] > 0 and d[5] > 0:
                    d[10] -= 1
                    d[5] -= 1
                    d[i] += 1
                elif d[5] > 2:
                    d[5] -= 3
                    d[i] += 1
                else: return False
        return True