860. Lemonade Change
https://leetcode.com/problems/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 don't have any change in hand at first. Return true if and only if you can provide every customer with correct change. Example 1: Input: [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: [5,5,10] Output: true Example 3: Input: [10,10] Output: fal...