Add book-store exercise

Author: keiravillekode

config.json

@@ -540,6 +540,14 @@
         "prerequisites": [],
         "difficulty": 5
       },
+      {
+        "slug": "book-store",
+        "name": "Book Store",
+        "uuid": "34f951b2-d379-48be-acc8-8bafc411ca9a",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 7
+      },
       {
         "slug": "connect",
         "name": "Connect",

exercises/practice/book-store/.docs/instructions.md

@@ -0,0 +1,61 @@
+# 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.
+
+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 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?
+
+- 2 copies of the first book
+- 2 copies of the second book
+- 2 copies of the third book
+- 1 copy of the fourth book
+- 1 copy of the fifth book
+
+One way of grouping these 8 books is:
+
+- 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
+
+Resulting in:
+
+- 5 × (100% - 25%) × $8 = 5 × $6.00 = $30.00, plus
+- 3 × (100% - 10%) × $8 = 3 × $7.20 = $21.60
+
+Which equals $51.60.
+
+However, a different way to group these 8 books is:
+
+- 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
+
+Resulting in:
+
+- 4 × (100% - 20%) × $8 = 4 × $6.40 = $25.60, plus
+- 4 × (100% - 20%) × $8 = 4 × $6.40 = $25.60
+
+Which equals $51.20.
+
+And $51.20 is the price with the biggest discount.

exercises/practice/book-store/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "keiravillekode"
+  ],
+  "files": {
+    "solution": [
+      "BookStore.pas"
+    ],
+    "test": [
+      "TestCases.pas"
+    ],
+    "example": [
+      ".meta/example.pas"
+    ]
+  },
+  "blurb": "To try and encourage more sales of different books from a popular 5 book series, a bookshop has decided to offer discounts of multiple-book purchases.",
+  "source": "Inspired by the harry potter kata from Cyber-Dojo.",
+  "source_url": "https://cyber-dojo.org/creator/home"
+}

exercises/practice/book-store/.meta/example.pas

@@ -0,0 +1,46 @@
+unit BookStore;
+
+{$mode ObjFPC}{$H+}
+
+interface
+
+function total(const basket : Array Of Integer) : integer;
+
+implementation
+
+uses Math, SysUtils;
+
+function total(const basket : Array Of Integer) : integer;
+var
+  tally : Array Of Integer = ();
+  i : Integer;
+  j : Integer;
+  temp : Integer;
+begin
+  for i := 0 to 5 do
+    insert(0, tally, length(tally));
+
+  for i := low(basket) to high(basket) do
+    tally[basket[i]] := tally[basket[i]] + 1;
+
+  for i := 4 downto 1 do
+    for j := i to 4 do
+      if tally[j] < tally[j + 1] then
+        begin
+          temp := tally[j];
+          tally[j] := tally[j + 1];
+          tally[j + 1] := temp;
+        end;
+
+  for i := 1 to 4 do
+    tally[i] := tally[i] - tally[i + 1];
+
+  temp := min(tally[3], tally[5]);
+  tally[3] := tally[3] - temp;
+  tally[5] := tally[5] - temp;
+  tally[4] := tally[4] + 2 * temp;
+
+  result := 5 * 600 * tally[5] + 4 * 640 * tally[4] + 3 * 720 * tally[3] + 2 * 760 * tally[2] + 1 * 800 * tally[1];
+end;
+
+end.

exercises/practice/book-store/.meta/tests.toml

@@ -0,0 +1,64 @@
+# 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"
+
+[cc2de9ac-ff2a-4efd-b7c7-bfe0f43271ce]
+description = "Two of the same book"
+
+[5a86eac0-45d2-46aa-bbf0-266b94393a1a]
+description = "Empty basket"
+
+[158bd19a-3db4-4468-ae85-e0638a688990]
+description = "Two different books"
+
+[f3833f6b-9332-4a1f-ad98-6c3f8e30e163]
+description = "Three different books"
+
+[1951a1db-2fb6-4cd1-a69a-f691b6dd30a2]
+description = "Four different books"
+
+[d70f6682-3019-4c3f-aede-83c6a8c647a3]
+description = "Five different books"
+
+[78cacb57-911a-45f1-be52-2a5bd428c634]
+description = "Two groups of four is cheaper than group of five plus group of three"
+
+[f808b5a4-e01f-4c0d-881f-f7b90d9739da]
+description = "Two groups of four is cheaper than groups of five and three"
+
+[fe96401c-5268-4be2-9d9e-19b76478007c]
+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 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 two each of remaining"
+
+[0b19a24d-e4cf-4ec8-9db2-8899a41af0da]
+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"

exercises/practice/book-store/BookStore.pas

@@ -0,0 +1,20 @@
+unit BookStore;
+
+{$mode ObjFPC}{$H+}
+
+interface
+
+function total(const basket : Array Of Integer) : integer;
+
+implementation
+
+uses SysUtils;
+
+function total(const basket : Array Of Integer) : integer;
+begin
+
+  raise ENotImplemented.Create('Please implement your solution.'); result := length(basket);
+
+end;
+
+end.

exercises/practice/book-store/Makefile

@@ -0,0 +1,15 @@
+SHELL       = /bin/bash
+MAKEFLAGS  += --no-print-directory
+DESTDIR     = build
+EXECUTABLE  = $(DESTDIR)/test
+COMMAND     = fpc -l- -v0 -g -gl -Sa -Cr -Sehnw -Fu./lib test.pas -FE"./$(DESTDIR)"
+
+.ONESHELL:
+
+test:
+	@mkdir -p "./$(DESTDIR)"
+	@cp -r ./lib "./$(DESTDIR)"
+	@$(COMMAND) && ./$(EXECUTABLE) $(test)
+
+clean:
+	@rm -fr "./$(DESTDIR)"