Take great care to buy the latest version: bit.ly/buyingEPI
EPI includes a framework for writing your solutions, as well as testing them against a comprehensive set of test-cases. Head over to judge.elementsofprogramminginterviews.com for details.
Before you buy this book, please first head over to our sample page - elementsofprogramminginterviews.com/sample

The sampler should give you a very good idea of the quality and style of our book. In particular, be sure you are comfortable with the level and with our Python coding style.
Since different candidates have different time constraints, EPI includes a study guide with several scenarios, ranging from weekend Hackathon to semester long preparation with a recommended a subset of problems for each scenario. 
All problems are classified in terms of their difficulty level and include many variants to help you apply what you have learned more widely.
All problems includes hints for readers who get stuck. This simulates what you will face in the real interview.
The version being sold by Amazon itself is always current. Some resellers may have older versions, especially if they sell used copies.