eulercli

A CLI for working on Project Euler problems

Overview

Project Euler is a wonderful, free resource for anyone interested in programming and mathematics.

The project offers a series of "challenging mathematical/computer programming problems". For those who learn best by doing, solving these problems is a fun and addictive way to learn a new programming language.

eulercli is a command-line interface for working on Project Euler problems. You can use it to

• Create template solution programs in julia or go -- eulercli generate 42 --language julia
• Check the output of your solution program -- julia mysolution.jl | eulercli check
• Echo problem text and hashed solutions -- eulercli problem 42

eulercli is written in go. I built it to give back to the Project Euler community, and to get some hands-on experience with cobra.

Installation

eulercli requires go 1.16 or later.

To install it, run

go install github.com/koomen/eulercli@latest

Make sure you've added GOBIN to your PATH. See go help install for more details on where to find GOBIN on your system.

You can verify your installation by running eulercli --version.

Usage

Echo problem text and (hashed) answers

eulercli will display many euler problems in plaintext:

$ eulercli problem 1
If we list all the natural numbers below 10 that are multiples of 3 or 5,
we get 3, 5, 6 and 9. The sum of these multiples is 23.

Find the sum of all the multiples of 3 or 5 below 1000.

It will also display the answer to many problems, hashed using MD5.

$ eulercli answer 1
e1edf9d1967ca96767dcc2b2d6df69f4

Generate an empty solution program

eulercli uses the go's text/template package to generate ready-to-use solution programs:

$ eulercli generate 25 --language julia
Writing generated solution files to ./julia
  Wrote file ./julia/src/euler0025/solution.jl
Have fun!

Download solution program template files

eulercli looks for solution template files in ./eulercli-templates. If this directory does not exist or if appropriate template files aren't found inside it, they can be downloaded on-the-fly from the eulercli-templates repository.

You can use eulercli pull to trigger this download manually:

$ eulercli pull
Downloading templates from https://github.com/koomen/eulercli
  Wrote file eulercli-templates/julia/initenv.jl
  Wrote file eulercli-templates/julia/src/euler{{.PaddedProblemNum}}/solution.jl
Successfully pulled template solution files to eulercli-templates

eulercli pull will download a fresh copy of these templates into your working directory, or update older template files they already exist. In that case, you'll be prompted to confirm before any files are overwritten.

Once you've downloaded template files into ./eulercli-templates, you can modify them or add your own. See the eulercli-templates repository for instructions.

Check your answers (using command line arguments)

eulercli can also be used to check answers:

$ eulercli check 1 <answer>
Congratulations, <answer> is the correct answer to problem 1!\n

Check your answers (using pipes)

You can also pipe the results of your solution program directly to eulercli for answer-checking. eulercli will echo your program's output to stdout and check it for the correct answer when your program terminates:

$ julia solution.jl | eulercli check
Scanning stdin for problem number and correct answer...
-------------------------------------------------------------------------------


solution.jl - Solve Project Euler problem 1
Usage: solution.jl [--profile|-p] [--benchmark|p]
Options:
    --benchmark,-b      Benchmark your solution
    --profile,-p        Profile your solution

 Activating new environment at `~/git/projecteuler/julia/src/projecteulerenv/Project.toml`
Solving project euler problem 1...
Obtained solution <answer>


-------------------------------------------------------------------------------
Extracted problem number 1 from input
Detected answer <answer> in input. 
Congratulations, this is the correct answer to problem 1!

How does this work? eulercli scans the output of your solution program.

If the problem number is not provided as an argument, the regular expression [Pp]roblem\s*(\d+) is used to extract the problem number, so as long as e.g. "Problem 5" or "problem 5" appears somewhere in your program's output, eulercli will be able to infer the problem number.

eulercli also scans your program's output for the correct answer. If it is found anywhere it your program's output, you should see:

Detected answer <answer> in input. Congratulations, this is the correct answer to problem 1!

If the correct answer is not found in your program's output, you'll see:

Failed to find correct answer for problem 1 in input.

Contributing

Code contributions to eulercli are encouraged and appreciated! If you'd like to contribute, clone this repository, commit your proposed changes, and create a pull request in this repository.

Acknowledgements

Problem text taken from David Corbin's Project Euler Offline and Kyle Keen's Local Euler projects.

Problem solutions taken from Bai Li's projecteuler-solutions repository.

eulercli makes extensive use of Steve Francia's wonderful cobra library