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.
Given an integer array bills where bills[i] is the bill the i^th 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
trueSince all customers got correct change, the output is true.
Example 2
Input
bills = [5,5,10,10,20]Output
falseFor the last customer, you cannot give $15 in change because you only have two $10 bills, so the output is false.
Constraints
- 1 <= bills.length <= 10^5
- bills[i] is either 5, 10, or 20.
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