Lemonade Change Lab

In this lab, you will be working on a problem related to a lemonade stand where each lemonade costs $5. Customers are standing in a queue to buy from you and order one at a time (in the order specified by bills). Each customer will only buy one lemonade and pay with either a $5, $10, or $20 bill. Your task is to provide the correct change to each customer so that the net transaction is that the customer pays $5.

At the beginning of the day, you have no change in hand. You are given an integer array bills where bills[i] is the bill the ith customer pays. You need to return true if you can provide every customer with the correct change, or false otherwise.

Examples

Example 1:

Input: bills = [5,5,5,10,20]
Output: true

Explanation:

• From the first 3 customers, we collect three $5 bills in order.
• From the fourth customer, we collect a $10billandgivebacka10\; bill\; and\; give\; back\; a$5.
• From the fifth customer, we give a $10billanda10\; bill\; and\; a$5 bill.
• Since all customers got the correct change, we output true.

Example 2:

Input: bills = [5,5,10,10,20]
Output: false

Explanation:

• From the first two customers in order, we collect two $5 bills.
• For the next two customers in order, we collect a $10billandgivebacka10\; bill\; and\; give\; back\; a$5 bill.
• For the last customer, we cannot give the change of $15backbecauseweonlyhavetwo15\; back\; because\; we\; only\; have\; two$10 bills.
• Since not every customer received the correct change, the answer is false.

Lab Challenges

1. Challenge 1: Write a function lemonadeChange() that takes an array bills as a parameter and returns a boolean value whether you can provide every customer with the correct change or not.
2. Challenge 2: Export the lemonadeChange() function.