2025-08-01 06:59:43 +0000 UTC

class Solution:
    def lemonadeChange(self, bills: List[int]) -> bool:
        change_5, change_10 = 0, 0
        for bill in bills:
            if bill == 5:
                change_5 += 1
            elif bill == 10 and change_5 > 0:
                change_5 -= 1
                change_10 += 1
            elif bill == 10 and change_5 <= 0:
                return False
            elif bill == 20 and change_10 > 0 and change_5 > 0:
                change_10 -= 1
                change_5 -= 1
            elif bill == 20 and change_5 >= 3:
                change_5 -= 3
            else:
                return False
        return True