exercism fetch scala book-store

Book Store

To try and encourage more sales of different books from a popular 5 book series, a bookshop has decided to offer discounts on multiple book purchases.

One copy of any of the five books costs $8.

If, however, you buy two different books, you get a 5% discount on those two books.

If you buy 3 different books, you get a 10% discount.

If you buy 4 different books, you get a 20% discount.

If you buy all 5, you get a 25% discount.

Note: that if you buy four books, of which 3 are different titles, you get a 10% discount on the 3 that form part of a set, but the fourth book still costs $8.

Your mission is to write a piece of code to calculate the price of any conceivable shopping basket (containing only books of the same series), giving as big a discount as possible.

For example, how much does this basket of books cost?

One way of grouping these 8 books is:

This would give a total of:

Resulting in:

For a total of $51.60

However, a different way to group these 8 books is:

This would give a total of:

Resulting in:

For a total of $51.20

And $51.20 is the price with the biggest discount.

The Scala exercises assume an SBT project scheme. The exercise solution source should be placed within the exercise directory/src/main/scala. The exercise unit tests can be found within the exercise directory/src/test/scala.

To run the tests simply run the command sbt test in the exercise directory.

For more detailed info about the Scala track see the help page.


Inspired by the harry potter kata from Cyber-Dojo. http://cyber-dojo.org

Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you can see how others have completed the exercise.