You want to buy a certain set of items. The shop offers you a discount percent discount on every third item you buy. Therefore, you want to purchase the items in an order that will minimize the total cost.
Given a int prices containing the prices of the desired items and an int discount, return the minimal amount of money you must have in order to buy all the items.
|-||Your return value must have an absolute or relative error less than 1e-9.|
|-||discount will be between 0 and 100, inclusive.|
|-||prices will contain between 0 and 50 elements, inclusive.|
|-||Each element of prices will be between 0 and 2147483647, inclusive.|