Url shortener

From Computer Science Wiki
This a problem set for you to work through [1]

This is a problem set. Some of these are easy, others are far more difficult. The purpose of these problems sets are:

  1. to build your skill applying computational thinking to a problem
  2. to assess your knowledge and skills of different programming practices

What is this problem set trying to do[edit]

In this example we are applying our knowledge of lists, conditionals, and processing user input

The Problem[edit]

I found this problem on Daily Coding Problem[2], and I love it.

Implement a URL shortener:

  • shorten(url), which shortens the url into a six-character alphanumeric string, such as zLg6wl.
  • restore(short), which expands the shortened string into the original url. If no such shortened string exists, return null.

Hacker edition[edit]

In the hacker version:

  1. Save the shortened URL's in a database.

How you will be assessed[edit]

Your solution will be graded using the following axis:


  • To what extent does your code implement the features required by our specification?
  • To what extent is there evidence of effort?


  • To what extent did your code meet specifications?
  • To what extent did your code meet unit tests?
  • To what extent is your code free of bugs?


  • To what extent is your code written well (i.e. clearly, efficiently, elegantly, and/or logically)?
  • To what extent is your code eliminating repetition?
  • To what extent is your code using functions appropriately?


  • To what extent is your code readable?
  • To what extent is your code commented?
  • To what extent are your variables well named?
  • To what extent do you adhere to style guide?


A possible solution[edit]

Click the expand link to see one possible solution, but NOT before you have tried and failed!

not yet!