There's no correct way to solve this, and take as much time as you need...we're just trying to get a look at your coding style and thought process.

Make sure to include the unit tests you write for this in your submission.

Given a list of words (words.tar.gz), generate two output files, 'questions' and 'answers'. 'questions' should contain every sequence of four letters that appears in exactly one word of the dictionary, one sequence per line. 'answers' should contain the corresponding words that contain the sequences, in the same order, again one per line.

An example:

Say this is your dictionary:

• arrows
• carrots
• give
• me

'questions' would contain:

• carr
• give
• rots
• rows
• rrot
• rrow

and 'answers' would have:

• carrots
• give
• carrots
• arrows
• carrots
• arrows

'arro' wouldn't show up in 'questions', because it appears in two words

1. Fork this repo
2. Create a feature branch for your solution (eg [github username]/solution)
3. Complete work
4. Open a pull request to submit.