I recommend "Cracking The Coding Interview" (https://amzn.to/2RjYkoG https://amzn.to/2RjYkoG) for the beginning. It is a good starting point. If your are famil

I recommend "Cracking The Coding Interview" (https://amzn.to/2RjYkoG https://amzn.to/2RjYkoG) for the beginning. It is a good starting point. If your are familiar with PHP, you can checkout my library based on CTCI: https://github.com/doganoo/PHPAlgorithms https://github.com/doganoo/PHPAlgorithms