New practice exercise relative-distance (#1554)

* run generator mix format from exercise folder

* inspect limit to infinity

* WIP

* finish up with updatet canonical data

* too many exercises with recursion

Author: jiegillet

bin/bootstrap_practice_exercise.exs

@@ -73,24 +73,24 @@ defmodule Generate do
         "# #{Enum.map_join(values, "\n# ", &String.trim/1)}"
 
       {field, values} when is_list(values) ->
-        "#\n# --#{field} --\n# #{Enum.map_join(values, "\n# ", &inspect/1)}"
+        "#\n# --#{field} --\n# #{Enum.map_join(values, "\n# ", &inspect(&1, limit: :infinity))}"
 
       {field, value} ->
-        "#\n# -- #{field} --\n# #{inspect(value)}"
+        "#\n# -- #{field} --\n# #{inspect(value, limit: :infinity)}"
     end)
   end
 
   def print_input(%{} = input),
     do:
       Enum.map_join(input, "\n", fn {variable, value} ->
-        "#{Macro.underscore(variable)} = #{inspect(value)}"
+        "#{Macro.underscore(variable)} = #{inspect(value, limit: :infinity)}"
       end)
 
-  def print_input(input), do: "input = #{inspect(input)}"
+  def print_input(input), do: "input = #{inspect(input, limit: :infinity)}"
 
-  def print_expected(%{"error" => err}, _error), do: "{:error, #{inspect(err)}}"
-  def print_expected(expected, true), do: "{:ok, #{inspect(expected)}}"
-  def print_expected(expected, false), do: inspect(expected)
+  def print_expected(%{"error" => err}, _error), do: "{:error, #{inspect(err, limit: :infinity)}}"
+  def print_expected(expected, true), do: "{:ok, #{inspect(expected, limit: :infinity)}}"
+  def print_expected(expected, false), do: inspect(expected, limit: :infinity)
 
   def print_test_case(
         %{"description" => description, "cases" => sub_cases} = category,
@@ -143,8 +143,9 @@ module =
 
 ## Step 1: create folder structure
 
-Mix.Generator.create_directory("exercises/practice/#{exercise}/lib")
-Mix.Generator.create_directory("exercises/practice/#{exercise}/test")
+File.cd!("exercises/practice/#{exercise}")
+Mix.Generator.create_directory("lib")
+Mix.Generator.create_directory("test")
 
 ## Step 2: add common files
 
@@ -156,7 +157,7 @@ format = """
 ]
 """
 
-Mix.Generator.create_file("exercises/practice/#{exercise}/.formatter.exs", format)
+Mix.Generator.create_file(".formatter.exs", format)
 
 # mix.exs
 mix = """
@@ -189,7 +190,7 @@ defmodule #{module}.MixProject do
 end
 """
 
-Mix.Generator.create_file("exercises/practice/#{exercise}/mix.exs", mix)
+Mix.Generator.create_file("mix.exs", mix)
 
 # .gitignore
 gitignore = """
@@ -221,15 +222,15 @@ erl_crash.dump
 /tmp/
 """
 
-Mix.Generator.create_file("exercises/practice/#{exercise}/.gitignore", gitignore)
+Mix.Generator.create_file(".gitignore", gitignore)
 
 # test/test_helper.exs
 test_helper = """
 ExUnit.start()
 ExUnit.configure(exclude: :pending, trace: true)
 """
 
-Mix.Generator.create_file("exercises/practice/#{exercise}/test/test_helper.exs", test_helper)
+Mix.Generator.create_file("test/test_helper.exs", test_helper)
 
 ## Step 3: write files that depend on problem specifications
 
@@ -256,10 +257,10 @@ defmodule #{module} do
 end
 """
 
-path = "exercises/practice/#{exercise}/lib/#{exercise_snake_case}.ex"
+path = "lib/#{exercise_snake_case}.ex"
 Mix.Generator.create_file(path, lib_file)
 
-Mix.Generator.copy_file(path, "exercises/practice/#{exercise}/.meta/example.ex")
+Mix.Generator.copy_file(path, ".meta/example.ex")
 
 # Generating test file
 test_file =
@@ -273,8 +274,8 @@ test_file =
   """
   |> String.replace("@tag", "# @tag", global: false)
 
-path = "exercises/practice/#{exercise}/test/#{exercise_snake_case}_test.exs"
+path = "test/#{exercise_snake_case}_test.exs"
 Mix.Generator.create_file(path, test_file)
 
 # mix format all files
-Mix.Tasks.Format.run(["exercises/practice/#{exercise}/**/*.{ex,exs}"])
+Mix.Tasks.Format.run(["**/*.{ex,exs}"])

config.json

@@ -2445,6 +2445,23 @@
         ],
         "difficulty": 6
       },
+      {
+        "slug": "relative-distance",
+        "name": "Relative Distance",
+        "uuid": "ba1d165a-774f-4b8f-9763-2d4279769e75",
+        "practices": [],
+        "prerequisites": [
+          "recursion",
+          "maps",
+          "tuples",
+          "lists",
+          "list-comprehensions",
+          "enum",
+          "multiple-clause-functions",
+          "nil"
+        ],
+        "difficulty": 6
+      },
       {
         "slug": "robot-simulator",
         "name": "Robot Simulator",

exercises/practice/relative-distance/.docs/instructions.md

@@ -0,0 +1,39 @@
+# Instructions
+
+Your task is to determine the degree of separation between two individuals in a family tree.
+
+- You will be given an input, with all parent names and their children.
+- Each name is unique, a child _can_ have one or two parents.
+- The degree of separation is defined as the shortest number of connections from one person to another.
+- If two individuals are not connected, return a value that represents "no known relationship."
+  Please see the test cases for the actual implementation.
+
+## Example
+
+Given the following family tree:
+
+```text
+      ┌──────────┐            ┌──────────┐ ┌───────────┐
+      │  Helena  │            │  Erdős   │ │  Shusaku  │
+      └───┬───┬──┘            └─────┬────┘ └──────┬────┘
+      ┌───┘   └───────┐             └──────┬──────┘
+      ▼               ▼                    ▼
+┌──────────┐     ┌────────┐          ┌──────────┐
+│   Isla   │     │  Tariq │          │   Kevin  │
+└────┬─────┘     └────┬───┘          └──────────┘
+     ▼                ▼
+┌─────────┐      ┌────────┐
+│   Uma   │      │ Morphy │
+└─────────┘      └────────┘
+```
+
+The degree of separation between Tariq and Uma is 3 (Tariq → Helena → Isla → Uma).
+There's no known relationship between Isla and [Kevin][six-bacons], as there is no connection in the given data.
+The degree of separation between Uma and Isla is 1.
+
+~~~~exercism/note
+Isla and Tariq are siblings and have a separation of 1.
+Similarly, this implementation would report a separation of 2 from you to your father's brother.
+~~~~
+
+[six-bacons]: https://en.m.wikipedia.org/wiki/Six_Degrees_of_Kevin_Bacon

exercises/practice/relative-distance/.docs/introduction.md

@@ -0,0 +1,12 @@
+# Introduction
+
+You've been hired to develop **Noble Knots**, the hottest new dating app for nobility!
+With centuries of royal intermarriage, things have gotten… _complicated_.
+To avoid any _oops-we're-twins_ situations, your job is to build a system that checks how closely two people are related.
+
+Noble Knots is inspired by Iceland's "[Islendinga-App][islendiga-app]," which is backed up by a database that traces all known family connections between Icelanders from the time of the settlement of Iceland.
+Your algorithm will determine the **degree of separation** between two individuals in the royal family tree.
+
+Will your app help crown a perfect match?
+
+[islendiga-app]: http://www.islendingaapp.is/information-in-english/

exercises/practice/relative-distance/.formatter.exs

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

exercises/practice/relative-distance/.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").
+relative_distance-*.tar
+
+# Temporary files, for example, from tests.
+/tmp/

exercises/practice/relative-distance/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "jiegillet"
+  ],
+  "files": {
+    "solution": [
+      "lib/relative_distance.ex"
+    ],
+    "test": [
+      "test/relative_distance_test.exs"
+    ],
+    "example": [
+      ".meta/example.ex"
+    ]
+  },
+  "blurb": "Given a family tree, calculate the degree of separation.",
+  "source": "vaeng",
+  "source_url": "https://github.com/exercism/problem-specifications/pull/2537"
+}

exercises/practice/relative-distance/.meta/example.ex

@@ -0,0 +1,42 @@
+defmodule RelativeDistance do
+  @doc """
+  Find the degree of separation of two members given a given family tree.
+  """
+  @spec degree_of_separation(
+          family_tree :: %{String.t() => [String.t()]},
+          person_a :: String.t(),
+          person_b :: String.t()
+        ) :: nil | pos_integer()
+  def degree_of_separation(family_tree, person_a, person_b) do
+    family_tree
+    |> build_family_graph()
+    |> find_separation(person_b, [{person_a, 0}], MapSet.new())
+  end
+
+  defp build_family_graph(family_tree) do
+    for {parent, children} <- family_tree, child <- children, reduce: %{} do
+      graph ->
+        siblings = children |> MapSet.new() |> MapSet.delete(child)
+
+        graph
+        |> Map.update(parent, MapSet.new([child]), &MapSet.put(&1, child))
+        |> Map.update(child, MapSet.new([parent]), &MapSet.put(&1, parent))
+        |> Map.update(child, siblings, &MapSet.union(&1, siblings))
+    end
+  end
+
+  defp find_separation(_graph, _goal, [], _history), do: nil
+
+  defp find_separation(_graph, goal, [{goal, count} | _], _history), do: count
+
+  defp find_separation(graph, goal, [{person, count} | rest], history) do
+    history = MapSet.put(history, person)
+
+    next_steps =
+      graph[person]
+      |> Enum.reject(fn relative -> MapSet.member?(history, relative) end)
+      |> Enum.map(fn relative -> {relative, count + 1} end)
+
+    find_separation(graph, goal, rest ++ next_steps, history)
+  end
+end

exercises/practice/relative-distance/.meta/tests.toml

@@ -0,0 +1,31 @@
+# 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.
+
+[4a1ded74-5d32-47fb-8ae5-321f51d06b5b]
+description = "Direct parent-child relation"
+
+[30d17269-83e9-4f82-a0d7-8ef9656d8dce]
+description = "Sibling relationship"
+
+[8dffa27d-a8ab-496d-80b3-2f21c77648b5]
+description = "Two degrees of separation, grandchild"
+
+[34e56ec1-d528-4a42-908e-020a4606ee60]
+description = "Unrelated individuals"
+
+[93ffe989-bad2-48c4-878f-3acb1ce2611b]
+description = "Complex graph, cousins"
+
+[2cc2e76b-013a-433c-9486-1dbe29bf06e5]
+description = "Complex graph, no shortcut, far removed nephew"
+
+[46c9fbcb-e464-455f-a718-049ea3c7400a]
+description = "Complex graph, some shortcuts, cross-down and cross-up, cousins several times removed, with unrelated family tree"

exercises/practice/relative-distance/lib/relative_distance.ex

@@ -0,0 +1,12 @@
+defmodule RelativeDistance do
+  @doc """
+  Find the degree of separation of two members given a given family tree.
+  """
+  @spec degree_of_separation(
+          family_tree :: %{String.t() => [String.t()]},
+          person_a :: String.t(),
+          person_b :: String.t()
+        ) :: nil | pos_integer()
+  def degree_of_separation(family_tree, person_a, person_b) do
+  end
+end

exercises/practice/relative-distance/mix.exs

@@ -0,0 +1,27 @@
+defmodule RelativeDistance.MixProject do
+  use Mix.Project
+
+  def project do
+    [
+      app: :relative_distance,
+      version: "0.1.0",
+      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