Lemonade Change
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.
You are 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 = [5,10,5,5,20]
Output: trueExplanation:
From first customer, we collect one $5 bill.
From second customer, we collect $10 bill and give back $5 bill.
From third and fourth customers, we collect two $5 bills.
From fifth customer, we collect $20 bill and give back one $10 bill and $5 bill.
Example 2:
Input: bills = [5,20,10,5]
Output: falseConstraints:
1 <= bills.length <= 100,000bills[i]is either5,10, or20.