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## Description

At a lemonade stand, 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. You must provide the correct change to each customer so that the net transaction is that the customer pays $5. Note that you do not have any change in hand at first. Given an integer array bills where bills[i] is the bill the ith customer pays, return true if you can provide every customer with the correct change, or false otherwise. 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 $10 bill and give back a$5.
From the fifth customer, we give a $10 bill and a$5 bill.
Since all customers got 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$10 bill and give back a $5 bill. For the last customer, we can not give the change of$15 back because we only have two \$10 bills.
Since not every customer received the correct change, the answer is false.


Constraints:

• 1 <= bills.length <= 105
• bills[i] is either 5, 10, or 20.