A supermarket wants to reward its best customer of each day, showing the customer's name on a screen in the supermarket. For that purpose, the customer's purchase amount is stored in an ArrayList and the customer's name is stored in a corresponding ArrayList.

Implement a method

public static String nameOfBestCustomer(ArrayList sales, ArrayList customers)

that returns the name of the customer with the largest sale.

Write a program that prompts the cashier to enter all prices and names, adds them to two array lists, calls the method that you implemented, and displays the result. Use a price of 0 as a sentinel.

Improve the program of Exercise P6.30 so that it displays the top customers, that is, the topN customers with the largest sales, where topN is a value that the user of the program supplies.

Implement a method

public static ArrayList nameOfBestCustomers(ArrayList sales,

ArrayList customers, int topN)

If there were fewer than topN customers, include all of them.