Skip to content

Commit

Permalink
sync book-store
Browse files Browse the repository at this point in the history
  • Loading branch information
tomasnorre committed Nov 14, 2024
1 parent 1df6486 commit d8eae7c
Show file tree
Hide file tree
Showing 2 changed files with 38 additions and 29 deletions.
39 changes: 16 additions & 23 deletions exercises/practice/book-store/.docs/instructions.md
Original file line number Diff line number Diff line change
@@ -1,27 +1,20 @@
# Instructions

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.
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, 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.
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.
Your mission is to write 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?

Expand All @@ -33,36 +26,36 @@ For example, how much does this basket of books cost?

One way of grouping these 8 books is:

- 1 group of 5 --> 25% discount (1st,2nd,3rd,4th,5th)
- +1 group of 3 --> 10% discount (1st,2nd,3rd)
- 1 group of 5 (1st, 2nd,3rd, 4th, 5th)
- 1 group of 3 (1st, 2nd, 3rd)

This would give a total of:

- 5 books at a 25% discount
- +3 books at a 10% discount
- 3 books at a 10% discount

Resulting in:

- 5 x (8 - 2.00) == 5 x 6.00 == $30.00
- +3 x (8 - 0.80) == 3 x 7.20 == $21.60
- 5 × (100% - 25%) × $8 = 5 × $6.00 = $30.00, plus
- 3 × (100% - 10%) × $8 = 3 × $7.20 = $21.60

For a total of $51.60
Which equals $51.60.

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

- 1 group of 4 books --> 20% discount (1st,2nd,3rd,4th)
- +1 group of 4 books --> 20% discount (1st,2nd,3rd,5th)
- 1 group of 4 books (1st, 2nd, 3rd, 4th)
- 1 group of 4 books (1st, 2nd, 3rd, 5th)

This would give a total of:

- 4 books at a 20% discount
- +4 books at a 20% discount
- 4 books at a 20% discount

Resulting in:

- 4 x (8 - 1.60) == 4 x 6.40 == $25.60
- +4 x (8 - 1.60) == 4 x 6.40 == $25.60
- 4 × (100% - 20%) × $8 = 4 × $6.40 = $25.60, plus
- 4 × (100% - 20%) × $8 = 4 × $6.40 = $25.60

For a total of $51.20
Which equals $51.20.

And $51.20 is the price with the biggest discount.
28 changes: 22 additions & 6 deletions exercises/practice/book-store/.meta/tests.toml
Original file line number Diff line number Diff line change
@@ -1,6 +1,13 @@
# This is an auto-generated file. Regular comments will be removed when this
# file is regenerated. Regenerating will not touch any manually added keys,
# so comments can be added in a "comment" key.
# This is an auto-generated file.
#
# Regenerating this file via `configlet sync` will:
# - Recreate every `description` key/value pair
# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
# - Preserve any other key/value pair
#
# As user-added comments (using the # character) will be removed when this file
# is regenerated, comments can be added via a `comment` key.

[17146bd5-2e80-4557-ab4c-05632b6b0d01]
description = "Only a single book"
Expand Down Expand Up @@ -33,16 +40,25 @@ description = "Two groups of four is cheaper than groups of five and three"
description = "Group of four plus group of two is cheaper than two groups of three"

[68ea9b78-10ad-420e-a766-836a501d3633]
description = "Two each of first 4 books and 1 copy each of rest"
description = "Two each of first four books and one copy each of rest"

[c0a779d5-a40c-47ae-9828-a340e936b866]
description = "Two copies of each book"

[18fd86fe-08f1-4b68-969b-392b8af20513]
description = "Three copies of first book and 2 each of remaining"
description = "Three copies of first book and two each of remaining"

[0b19a24d-e4cf-4ec8-9db2-8899a41af0da]
description = "Three each of first 2 books and 2 each of remaining books"
description = "Three each of first two books and two each of remaining books"

[bb376344-4fb2-49ab-ab85-e38d8354a58d]
description = "Four groups of four are cheaper than two groups each of five and three"

[5260ddde-2703-4915-b45a-e54dbbac4303]
description = "Check that groups of four are created properly even when there are more groups of three than groups of five"

[b0478278-c551-4747-b0fc-7e0be3158b1f]
description = "One group of one and four is cheaper than one group of two and three"

[cf868453-6484-4ae1-9dfc-f8ee85bbde01]
description = "One group of one and two plus three groups of four is cheaper than one group of each size"

0 comments on commit d8eae7c

Please sign in to comment.