Project Euler CLI Questions and Answers in Ruby

This repo is not for everyone - most people will find it completely unnecessary. Everything was completely taken from Project Euler. 100% of all credit goes to those fine folks.

For decades, I have worked in vim within tmux in a terminal - either on a small laptop or a headless server. Submitting answers through a website just isn't for me. I find it to be a clunky waste of time.

But mostly I did this to reacquaint myself with a bare-bones (i.e., not Rails) Ruby app after years of primarily building in Clojure (a lovely, but nearly-completely unsupported fringe language - highly not recommended for commercial/production purposes - you'll just end up using Java libs) and Golang (fantastic for certain use cases - wouldn't call it the most agile language, but gosh I love it).

For the one other human being who is wacky like me, feel free to clone this repo, install the required version of Ruby declared in .ruby-version (in my opinion, rbenv is great for that), then

gem install bundler
bundle install

To solve the questions in Ruby:

bundle exec ruby run.rb

Or even better, install entr:

ls lib/euler/exercise/*.rb | entr bundle exec ruby run.rb

This will run the exercises in order. Ensure that the predefined my_solution function returns the correct solution in any fashion you'd like to get the correct answer.

This uses Ruby floats so the precision is limited to about 16 significant figures which could result in a false positive for a few questions. Also, comma separated values are supported (return a string) when needed, as are full text answers. If you're stuck, just return the string 'SKIP' (or use the __SKIP__ variable) to go on to the next question.

Alternately, you can submit answers through the CLI by using the included rake tasks. To view all available, rake tasks, run

bundle exec rake -T

The main and default task is:

bundle exec rake run_all

or simply

bundle exec rake

This will show all of the Project Euler questions in order. All you have to do is submit your answer (or 'SKIP') at the prompt, it will tell you if it's correct, save the success locally (./lib/user_solutions.csv), then display the next question.

Again, this is useless for ~99.9+% of people - especially those who don't live inside of a terminal. If you use an IDE, or are new to coding, just use the Project Euler website. It keeps track of your ranking too. I think...