1 class Cashier: 2 def __init__(self, n: int, discount: int, products: 'List[int]', prices: 'List[int]'): 3 self.customer_num = 0 4 self.dic = {} 5 m = len(products) 6 for i in range(m): 7 self.dic[products[i]] = prices[i] 8 self.n = n 9 self.discount = discount 10 11 12 def getBill(self, product: 'List[int]', amount: 'List[int]') -> float: 13 self.customer_num += 1 14 self.customer_num %= self.n 15 m = len(product) 16 total_amount = 0 17 for i in range(m): 18 productid = product[i] 19 amt = amount[i] 20 total_amount += (self.dic[productid] * amt) 21 if self.customer_num == 0: 22 total_amount = total_amount - (self.discount * total_amount) / 100 23 return total_amount
算法思路：将products[]与prices[]建立映射字典，这样可以方便查询每一种商品对应的单价。
每增加一个用户，累加一次用户数量，并用n进行求模运算，每第n个用户就计算折扣。
