[#722] New practice exercise yacht (#760)

Co-authored-by: Angelika Tyborska <[email protected]>

config.json

@@ -2429,6 +2429,25 @@
           "basics"
         ],
         "difficulty": 4
+      },
+      {
+        "slug": "yacht",
+        "name": "Yacht",
+        "uuid": "d2ee3ff4-2f01-404a-a4f0-d15823ac0482",
+        "prerequisites": [
+          "lists",
+          "cond",
+          "case",
+          "if",
+          "multiple-clause-functions",
+          "pattern-matching",
+          "guards",
+          "enum"
+        ],
+        "practices": [
+          "multiple-clause-matching"
+        ],
+        "difficulty": 5
       }
     ],
     "foregone": [

exercises/practice/yacht/.docs/instructions.md

@@ -0,0 +1,35 @@
+# Score a single throw of dice in *Yacht*
+
+The dice game [Yacht](https://en.wikipedia.org/wiki/Yacht_(dice_game)) is from
+the same family as Poker Dice, Generala and particularly Yahtzee, of which it
+is a precursor. In the game, five dice are rolled and the result can be entered
+in any of twelve categories. The score of a throw of the dice depends on
+category chosen.
+
+## Scores in Yacht
+
+| Category | Score | Description | Example |
+| -------- | ----- | ----------- | ------- |
+| Ones | 1 × number of ones | Any combination	| 1 1 1 4 5 scores 3 |
+| Twos | 2 × number of twos | Any combination | 2 2 3 4 5 scores 4 |
+| Threes | 3 × number of threes | Any combination | 3 3 3 3 3 scores 15 |
+| Fours | 4 × number of fours | Any combination | 1 2 3 3 5 scores 0 |
+| Fives | 5 × number of fives| Any combination | 5 1 5 2 5 scores 15 |
+| Sixes | 6 × number of sixes | Any combination | 2 3 4 5 6 scores 6 |
+| Full House | Total of the dice | Three of one number and two of another | 3 3 3 5 5 scores 19 |
+| Four of a Kind | Total of the four dice | At least four dice showing the same face | 4 4 4 4 6 scores 16 |
+| Little Straight |  30 points | 1-2-3-4-5 | 1 2 3 4 5 scores 30 |
+| Big Straight | 30 points | 2-3-4-5-6 | 2 3 4 5 6 scores 30 |
+| Choice | Sum of the dice | Any combination | 2 3 3 4 6 scores 18 |
+| Yacht | 50 points | All five dice showing the same face | 4 4 4 4 4 scores 50 |
+
+If the dice do not satisfy the requirements of a category, the score is zero.
+If, for example, *Four Of A Kind* is entered in the *Yacht* category, zero
+points are scored. A *Yacht* scores zero if entered in the *Full House* category.
+
+## Task
+Given a list of values for five dice and a category, your solution should return
+the score of the dice for that category. If the dice do not satisfy the requirements
+of the category your solution should return 0. You can assume that five values
+will always be presented, and the value of each will be between one and six
+inclusively. You should not assume that the dice are ordered.

exercises/practice/yacht/.formatter.exs

@@ -0,0 +1,4 @@
+# Used by "mix format"
+[
+  inputs: ["{mix,.formatter}.exs", "{config,lib,test}/**/*.{ex,exs}"]
+]

exercises/practice/yacht/.gitignore

@@ -0,0 +1,26 @@
+# The directory Mix will write compiled artifacts to.
+/_build/
+
+# If you run "mix test --cover", coverage assets end up here.
+/cover/
+
+# The directory Mix downloads your dependencies sources to.
+/deps/
+
+# Where third-party dependencies like ExDoc output generated docs.
+/doc/
+
+# Ignore .fetch files in case you like to edit your project deps locally.
+/.fetch
+
+# If the VM crashes, it generates a dump, let's ignore it too.
+erl_crash.dump
+
+# Also ignore archive artifacts (built via "mix archive.build").
+*.ez
+
+# Ignore package tarball (built via "mix hex.build").
+yacht-*.tar
+
+# Temporary files, for example, from tests.
+/tmp/

exercises/practice/yacht/.meta/config.json

@@ -0,0 +1,22 @@
+{
+  "blurb": "Score a single throw of dice in the game Yacht." ,
+  "authors": [
+    "elibdev"
+  ],
+  "contributors": [
+    "angelikatyborska"
+  ],
+  "files": {
+    "solution": [
+      "lib/yacht.ex"
+    ],
+    "test": [
+      "test/yacht_test.exs"
+    ],
+    "example": [
+      ".meta/example.ex"
+    ]
+  },
+  "source": "James Kilfiger, using wikipedia",
+  "source_url": "https://en.wikipedia.org/wiki/Yacht_(dice_game)"
+}

exercises/practice/yacht/.meta/example.ex

@@ -0,0 +1,95 @@
+defmodule Yacht do
+  @type category ::
+          :ones
+          | :twos
+          | :threes
+          | :fours
+          | :fives
+          | :sixes
+          | :full_house
+          | :four_of_a_kind
+          | :little_straight
+          | :big_straight
+          | :choice
+          | :yacht
+
+  defp die_frequencies(dice) do
+    Enum.reduce(dice, %{}, fn die, frequencies ->
+      Map.update(frequencies, die, 1, &(&1 + 1))
+    end)
+  end
+
+  @doc """
+  Calculate the score of the list of 5 dice rolls using the given category.
+  """
+  @spec score(category :: category(), dice :: [integer]) :: integer
+  def score(category, dice)
+
+  def score(:ones, dice), do: score(1, dice)
+  def score(:twos, dice), do: score(2, dice)
+  def score(:threes, dice), do: score(3, dice)
+  def score(:fours, dice), do: score(4, dice)
+  def score(:fives, dice), do: score(5, dice)
+  def score(:sixes, dice), do: score(6, dice)
+
+  def score(number, dice) when is_integer(number) do
+    Enum.count(dice, &(&1 == number)) * number
+  end
+
+  def score(:full_house, dice) do
+    full_house =
+      die_frequencies(dice)
+      |> Map.values()
+      |> MapSet.new() == MapSet.new([3, 2])
+
+    if full_house do
+      Enum.sum(dice)
+    else
+      0
+    end
+  end
+
+  def score(:four_of_a_kind, dice) do
+    frequencies =
+      die_frequencies(dice)
+      |> Enum.to_list()
+      |> Enum.filter(fn {_, frequency} -> frequency >= 4 end)
+
+    case frequencies do
+      [{number, _frequencies}] ->
+        number * 4
+
+      _ ->
+        0
+    end
+  end
+
+  def score(:little_straight, dice) do
+    if MapSet.new(dice) == MapSet.new([1, 2, 3, 4, 5]) do
+      30
+    else
+      0
+    end
+  end
+
+  def score(:big_straight, dice) do
+    if MapSet.new(dice) == MapSet.new([2, 3, 4, 5, 6]) do
+      30
+    else
+      0
+    end
+  end
+
+  def score(:choice, dice) do
+    Enum.sum(dice)
+  end
+
+  def score(:yacht, dice) do
+    unique_dice = MapSet.size(MapSet.new(dice))
+
+    case unique_dice do
+      1 -> 50
+      _ -> 0
+    end
+  end
+end

exercises/practice/yacht/.meta/tests.toml

@@ -0,0 +1,88 @@
+# 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.
+
+[3060e4a5-4063-4deb-a380-a630b43a84b6]
+description = "Yacht"
+
+[15026df2-f567-482f-b4d5-5297d57769d9]
+description = "Not Yacht"
+
+[36b6af0c-ca06-4666-97de-5d31213957a4]
+description = "Ones"
+
+[023a07c8-6c6e-44d0-bc17-efc5e1b8205a]
+description = "Ones, out of order"
+
+[7189afac-cccd-4a74-8182-1cb1f374e496]
+description = "No ones"
+
+[793c4292-dd14-49c4-9707-6d9c56cee725]
+description = "Twos"
+
+[dc41bceb-d0c5-4634-a734-c01b4233a0c6]
+description = "Fours"
+
+[f6125417-5c8a-4bca-bc5b-b4b76d0d28c8]
+description = "Yacht counted as threes"
+
+[464fc809-96ed-46e4-acb8-d44e302e9726]
+description = "Yacht of 3s counted as fives"
+
+[e8a036e0-9d21-443a-8b5f-e15a9e19a761]
+description = "Sixes"
+
+[51cb26db-6b24-49af-a9ff-12f53b252eea]
+description = "Full house two small, three big"
+
+[1822ca9d-f235-4447-b430-2e8cfc448f0c]
+description = "Full house three small, two big"
+
+[b208a3fc-db2e-4363-a936-9e9a71e69c07]
+description = "Two pair is not a full house"
+
+[b90209c3-5956-445b-8a0b-0ac8b906b1c2]
+description = "Four of a kind is not a full house"
+
+[32a3f4ee-9142-4edf-ba70-6c0f96eb4b0c]
+description = "Yacht is not a full house"
+
+[b286084d-0568-4460-844a-ba79d71d79c6]
+description = "Four of a Kind"
+
+[f25c0c90-5397-4732-9779-b1e9b5f612ca]
+description = "Yacht can be scored as Four of a Kind"
+
+[9f8ef4f0-72bb-401a-a871-cbad39c9cb08]
+description = "Full house is not Four of a Kind"
+
+[b4743c82-1eb8-4a65-98f7-33ad126905cd]
+description = "Little Straight"
+
+[7ac08422-41bf-459c-8187-a38a12d080bc]
+description = "Little Straight as Big Straight"
+
+[97bde8f7-9058-43ea-9de7-0bc3ed6d3002]
+description = "Four in order but not a little straight"
+
+[cef35ff9-9c5e-4fd2-ae95-6e4af5e95a99]
+description = "No pairs but not a little straight"
+
+[fd785ad2-c060-4e45-81c6-ea2bbb781b9d]
+description = "Minimum is 1, maximum is 5, but not a little straight"
+
+[35bd74a6-5cf6-431a-97a3-4f713663f467]
+description = "Big Straight"
+
+[87c67e1e-3e87-4f3a-a9b1-62927822b250]
+description = "Big Straight as little straight"
+
+[c1fa0a3a-40ba-4153-a42d-32bc34d2521e]
+description = "No pairs but not a big straight"
+
+[207e7300-5d10-43e5-afdd-213e3ac8827d]
+description = "Choice"
+
+[b524c0cf-32d2-4b40-8fb3-be3500f3f135]
+description = "Yacht as choice"
+

exercises/practice/yacht/lib/yacht.ex

@@ -0,0 +1,22 @@
+defmodule Yacht do
+  @type category ::
+          :ones
+          | :twos
+          | :threes
+          | :fours
+          | :fives
+          | :sixes
+          | :full_house
+          | :four_of_a_kind
+          | :little_straight
+          | :big_straight
+          | :choice
+          | :yacht
+
+  @doc """
+  Calculate the score of 5 dice using the given category's scoring method.
+  """
+  @spec score(category :: category(), dice :: [integer]) :: integer
+  def score(category, dice) do
+  end
+end

exercises/practice/yacht/mix.exs

@@ -0,0 +1,28 @@
+defmodule Yacht.MixProject do
+  use Mix.Project
+
+  def project do
+    [
+      app: :yacht,
+      version: "0.1.0",
+      # elixir: "~> 1.8",
+      start_permanent: Mix.env() == :prod,
+      deps: deps()
+    ]
+  end
+
+  # Run "mix help compile.app" to learn about applications.
+  def application do
+    [
+      extra_applications: [:logger]
+    ]
+  end
+
+  # Run "mix help deps" to learn about dependencies.
+  defp deps do
+    [
+      # {:dep_from_hexpm, "~> 0.3.0"},
+      # {:dep_from_git, git: "https://github.com/elixir-lang/my_dep.git", tag: "0.1.0"}
+    ]
+  end
+end

exercises/practice/yacht/test/test_helper.exs

@@ -0,0 +1,2 @@
+ExUnit.start()
+ExUnit.configure(exclude: :pending, trace: true)