Code Practice

Interviews GitHub Repo from kdn251 - great collection of solutions to code challenges from Cracking The Coding Interview, LeetCode, as well as from select companies (Google, Facebook and Amazon, for example). Recommend that you attempt your solution first and then take a peek here.

CodeQuizzes - Beginner-friendly way to cover some topics before an interview, flashcard style. CS concepts are not that deep nor wide but it's great for checking more language specific quirks.

RegEx Crossword Who even knew that this existed. If you hate RegEx, this will give you nightmares, or could quite possibly give you a whole new appreciation for it. If you'd like to learn there are some tutorials and challenges to help you overcome your fear of RegEx.

Chicago Tech Interviews

Practice Code Challenges

CodeFights - competing against a bot and earn coins that you can exchange for things! Great for beginners and those who love graphical interfaces. There's a study plan that focuses specifically on Interview Practice. Be sure to click on the topics button as they have a very nice overview of data structures, going over Big O. For example: Arrays.

HackerRank - You do need to read/parse the file before you even have something to work with, though. So be sure to do this exercise, first and bookmark, as not all challenges will include stdin/stdout code and then you'll be wondering forever, why your code is not passing or returns an error: Solve Me First. Bonus: Author of Cracking the Coding Interview, Gayle Laakmann McDowell, put together some videos for HackerRank, going over some of the problems from the book. Clear and to the point. HackerRank Cracking the Coding Interview Challenges

Leet Code - geared towards interviewing but levels of challenge difficulty range from Easy to Hard. Premium subscribers can get mock interviews utilizing questions for companies like Google or Facebook.

Exercism - there's some setup involved like installing the Command-Line Client, but there's a test suite included so you can practice Test-Driven Development and the command line. You can compare to other submissions and get feedback, and have different iterations of your code if you want to optimize its performance. And you'll have a local copy of your code.

Firecode - Firecode judges your current level of algorithms knowledge and utilizes that to assign problems to stretch your knowledge. The difficulty of the problems slowly increases as you solve more problems and level up. It encourages you to review problems you've seen before and also includes hints for when you're stuck on a problem.