Provide a set of positive integers (an array of integers). Each integer represent number of nights user request on Airbnb.com. If you are a host, you need to design and implement an algorithm to find out the maximum number a nights you can accommodate. The constrain is that you have to reserve at least one day between each request, so that you have time to clean the room.
Example:
1) Input: [1, 2, 3] ===> output: 4, because you will pick 1 and 3
2) input: [5, 1, 2, 6] ===> output: 11, because you will pick 5 and 6
3) input: [5, 1, 2, 6, 20, 2] ===> output: 27, because you will pick 5, 2, 20
