1. https://www.interviewcake.com/article/python/big-o-notation-time-and-space-complexity

    A primer on Big-O Notation. The simple and clear examples illustrate how to determine the worst case runtime of a given algorithm

  2. https://www.youtube.com/playlist?list=PLGLfVvz_LVvSX7fVd4OUFp_ODd86H0ZIY

    Learn: code, c++, python, java, php, mysql, javascript, js, html, css, go, ruby, sass, susy, objective c, swift, lua, c#, lisp, haskell, prolgo, scala, dart, jquery, handlebars, bootstrap, express, xampp, jade, MEAN stack, perl, groovy, rush, bash, typescript, erlang, elixir, f#, ES6, kotlin, crochet, r, clojure, arduino, crysal, julia, matlab, fortran, LaTeX, java in one video.

  3. http://www.pythontutor.com

    Write code in your web browser, see it visualized step by step, and get live help from volunteers. java, c, c++, javascript, ruby also available.

  4. https://www.humblebundle.com/books/artificial-intelligence-books