04. [Coding Interview Class](https://codinginterviewclass.com/)

05. [Competitive Programmer’s Handbook](https://cses.fi/book/book.pdf)

Learn the following modules by heart. Just knowing all of the following items will made most of the problem one-liners.

01. [itertools - Functions creating iterators for efficient looping](https://docs.python.org/3/library/itertools.html) - They will help you, more often than you think

02. [collections - High-performance container datatypes](https://docs.python.org/3/library/collections.html) - Believe me, this is pretty awesome