Write a program which computes the price of a macaron order?

Question

 I am really stuck with this question. I need your help please to write this program.

•   Each macaron has the same unit price(given as input) 
•   Each macaron has a specific flavor

An order is made of one or more sets A specific set can contain up to 5 macarons but cannot contain macarons of identical flavors. The order of macaron doesn't matter but the baker tries to fill up his 5-slots sets.

The baker offers a discount based on the number of different flavors in a set

•  2 diffrent flavours in the set = -10% on the price of the set
•  3 diffrent flavours in the set = -20% on the price of the set
•  4 diffrent flavours in the set = -10% on the price of the set
•  5 different flavours in the set =-40% on the price of the set

Implement the method ComputeTotalPrice(unitPrice,macarons) which

• takes as parameters unitPrice, a macaron unit price and macarons an array of strings corresponding to each macaron flavor
• returns the total price of the order as an integer(rounded down if the total is a float number)