Some Algorithms and their Solutions.
You can download the solution and play. Each algorithm is comented, you only need to uncoment and run a test to verify its funtionality. For example: If you want to check how Flipping Bits works, you can to open the MainActivity and uncoment the object to test it.
This isn't an app. It is only to store all my prep kits from Hacker Rank. Each of them is encapsulated in its class into the algorithms package.