grind is an ultra-simple CLI tool to help schedule reviews of LeetCode (or HackerRank, or Codeforces, etc) practice problems using spaced repetition, a proven method for effective learning and long-term retention. It is based on the SuperMemo 2 algorithm, a variant of which is used by the widely popular flashcard app Anki.

I have been slowly building it and using it as my personal tracking tool for a few months now, and decided to polish it up for others to use. That being said, it hasn't been well-tested on different OSes and terminals; please feel free to open issues or PRs if you come across bugs.

The easiest way to install grind is to open up a terminal of your choice and copy and paste in the following command:

curl -s https://raw.githubusercontent.com/brandon-gong/grind/main/install.sh | bash -s

This will install grind to a hidden folder named .grind/ in your home directory, and then update the startup script of your shell (.bashrc, .zshrc, or config.fish) to add that newly-created folder to your $PATH so you'll be able to run the grind command from anywhere. After installing, restart your terminal for the changes to be recognized.

For more advanced installation, you can git clone this repo anywhere you like (or just download the grind script file directly) and add it to your $PATH manually. Typically, grind assumes the data it stores is located in the same directory as itself, but you may customize the location by setting $GRIND_DATA_DIR in your environment.

To completely uninstall grind, you simply need to

• Delete the .grind folder
• (Optionally) remove the line from your shell's startup script (e.g. .bashrc) that adds .grind to your $PATH.

Once installed, you can start running grind just like this:

grind

This will start a REPL that will present you with old problems to review, or prompt you to provide a link to a new problem to learn if you're all caught up with reviewing.

If you just installed grind, there won't be any problems in the system yet, so you'll be faced with the latter case. So go to LeetCode, hit "Pick One", and paste the link into the prompt!

Side note: Nothing's stopping you from pasting in a HackerRank or Codeforces link instead, or something that is not a link at all, but as of now it cannot include spaces. This is on the TODO list to fix.

Regardless of if it is a new problem or a review, you will be presented with an opportunity to grade yourself after each question. The grades are as follows (the prompt will also include this message, so no need to memorize these):

Be honest with yourself! Nobody is looking!

Depending on the grade you provide, the problem will be scheduled to be reviewed after a certain time has passed. The idea is that you do not look at this problem between now and then; you allow yourself to "forget about it", so that when you see it again next it gets more firmly planted in your long-term memory.

Continue your practice session as long as you'd like. You can exit out of grind at any point by hitting Ctrl+C or Ctrl+D (Cmd for Mac users). Your data is automatically saved.

To get an idea of how many problems you've entered into the system and how many problems are due, you can run

grind status

And if you'd ever like a quick reminder of the commands without having to come back to this README, just run

grind help

I am quite content with where it is at now, and am not looking to turn this into some giant unmaintainable shell script. However, here are some additional features that could be implemented:

• Allow spaces in user input. Need to delimit by something other than spaces in the grind.data file.
• Allow users to tag different problems, e.g. tree, dp, and filter/review specific tags only.
• Allow users to remove problems using the CLI. I could forsee some problems getting annoying if the user has seen it too much.