anagram

elixir/anagram/.exercism/config.json

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+{
+  "authors": [
+    "rubysolo"
+  ],
+  "contributors": [
+    "andrewsardone",
+    "angelikatyborska",
+    "Br1ght0ne",
+    "Cohen-Carlisle",
+    "crazymykl",
+    "dalexj",
+    "devonestes",
+    "henrik",
+    "jeremy-w",
+    "jinyeow",
+    "kytrinyx",
+    "lpil",
+    "markijbema",
+    "neenjaw",
+    "parkerl",
+    "pminten",
+    "sotojuan",
+    "Teapane",
+    "tjcelaya",
+    "waiting-for-dev"
+  ],
+  "files": {
+    "solution": [
+      "lib/anagram.ex"
+    ],
+    "test": [
+      "test/anagram_test.exs"
+    ],
+    "example": [
+      ".meta/example.ex"
+    ]
+  },
+  "blurb": "Given a word and a list of possible anagrams, select the correct sublist.",
+  "source": "Inspired by the Extreme Startup game",
+  "source_url": "https://github.com/rchatley/extreme_startup"
+}

elixir/anagram/.exercism/metadata.json

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+{"track":"elixir","exercise":"anagram","id":"0ffb252576fd4b4fad8cdd024185d2be","url":"https://exercism.org/tracks/elixir/exercises/anagram","handle":"negrienko","is_requester":true,"auto_approve":false}

elixir/anagram/.formatter.exs

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

elixir/anagram/.gitignore

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+# 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").
+anagram-*.tar
+

elixir/anagram/HELP.md

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+# Help
+
+## Running the tests
+
+From the terminal, change to the base directory of the exercise then execute the tests with:
+
+```bash
+$ mix test
+```
+
+This will execute the test file found in the `test` subfolder -- a file ending in `_test.exs`
+
+Documentation:
+
+* [`mix test` - Elixir's test execution tool](https://hexdocs.pm/mix/Mix.Tasks.Test.html)
+* [`ExUnit` - Elixir's unit test library](https://hexdocs.pm/ex_unit/ExUnit.html)
+
+## Pending tests
+
+In test suites of practice exercises, all but the first test have been tagged to be skipped.
+
+Once you get a test passing, you can unskip the next one by commenting out the relevant `@tag :pending` with a `#` symbol.
+
+For example:
+
+```elixir
+# @tag :pending
+test "shouting" do
+  assert Bob.hey("WATCH OUT!") == "Whoa, chill out!"
+end
+```
+
+If you wish to run all tests at once, you can include all skipped test by using the `--include` flag on the `mix test` command:
+
+```bash
+$ mix test --include pending
+```
+
+Or, you can enable all the tests by commenting out the `ExUnit.configure` line in the file `test/test_helper.exs`.
+
+```elixir
+# ExUnit.configure(exclude: :pending, trace: true)
+```
+
+## Useful `mix test` options
+
+* `test/<FILE>.exs:LINENUM` - runs only a single test, the test from `<FILE>.exs` whose definition is on line `LINENUM`
+* `--failed` - runs only tests that failed the last time they ran
+* `--max-failures` - the suite stops evaluating tests when this number of test failures
+is reached
+* `--seed 0` - disables randomization so the tests in a single file will always be ran
+in the same order they were defined in
+
+## Submitting your solution
+
+You can submit your solution using the `exercism submit lib/anagram.ex` command.
+This command will upload your solution to the Exercism website and print the solution page's URL.
+
+It's possible to submit an incomplete solution which allows you to:
+
+- See how others have completed the exercise
+- Request help from a mentor
+
+## Need to get help?
+
+If you'd like help solving the exercise, check the following pages:
+
+- The [Elixir track's documentation](https://exercism.org/docs/tracks/elixir)
+- The [Elixir track's programming category on the forum](https://forum.exercism.org/c/programming/elixir)
+- [Exercism's programming category on the forum](https://forum.exercism.org/c/programming/5)
+- The [Frequently Asked Questions](https://exercism.org/docs/using/faqs)
+
+Should those resources not suffice, you could submit your (incomplete) solution to request mentoring.
+
+If you're stuck on something, it may help to look at some of the [available resources](https://exercism.org/docs/tracks/elixir/resources) out there where answers might be found.

elixir/anagram/README.md

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+# Anagram
+
+Welcome to Anagram on Exercism's Elixir Track.
+If you need help running the tests or submitting your code, check out `HELP.md`.
+
+## Introduction
+
+At a garage sale, you find a lovely vintage typewriter at a bargain price!
+Excitedly, you rush home, insert a sheet of paper, and start typing away.
+However, your excitement wanes when you examine the output: all words are garbled!
+For example, it prints "stop" instead of "post" and "least" instead of "stale."
+Carefully, you try again, but now it prints "spot" and "slate."
+After some experimentation, you find there is a random delay before each letter is printed, which messes up the order.
+You now understand why they sold it for so little money!
+
+You realize this quirk allows you to generate anagrams, which are words formed by rearranging the letters of another word.
+Pleased with your finding, you spend the rest of the day generating hundreds of anagrams.
+
+## Instructions
+
+Your task is to, given a target word and a set of candidate words, to find the subset of the candidates that are anagrams of the target.
+
+An anagram is a rearrangement of letters to form a new word: for example `"owns"` is an anagram of `"snow"`.
+A word is _not_ its own anagram: for example, `"stop"` is not an anagram of `"stop"`.
+
+The target and candidates are words of one or more ASCII alphabetic characters (`A`-`Z` and `a`-`z`).
+Lowercase and uppercase characters are equivalent: for example, `"PoTS"` is an anagram of `"sTOp"`, but `StoP` is not an anagram of `sTOp`.
+The anagram set is the subset of the candidate set that are anagrams of the target (in any order).
+Words in the anagram set should have the same letter case as in the candidate set.
+
+Given the target `"stone"` and candidates `"stone"`, `"tones"`, `"banana"`, `"tons"`, `"notes"`, `"Seton"`, the anagram set is `"tones"`, `"notes"`, `"Seton"`.
+
+## Source
+
+### Created by
+
+- @rubysolo
+
+### Contributed to by
+
+- @andrewsardone
+- @angelikatyborska
+- @Br1ght0ne
+- @Cohen-Carlisle
+- @crazymykl
+- @dalexj
+- @devonestes
+- @henrik
+- @jeremy-w
+- @jinyeow
+- @kytrinyx
+- @lpil
+- @markijbema
+- @neenjaw
+- @parkerl
+- @pminten
+- @sotojuan
+- @Teapane
+- @tjcelaya
+- @waiting-for-dev
+
+### Based on
+
+Inspired by the Extreme Startup game - https://github.com/rchatley/extreme_startup

elixir/anagram/lib/anagram.ex

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+defmodule Anagram do
+  @doc """
+  Returns all candidates that are anagrams of, but not equal to, 'base'.
+  """
+  @spec match(String.t(), [String.t()]) :: [String.t()]
+  def match(base, candidates) do
+    candidates
+    |> Enum.filter(&anagram?(normalize(base), normalize(&1)))
+  end
+
+  defp anagram?(base, base), do: false
+  defp anagram?(base, candidate), do: hash(base) == hash(candidate)
+
+  @spec normalize(String.t()) :: String.t()
+  defp normalize(string), do: string |> String.downcase() |> String.graphemes()
+
+  @spec hash(String.t()) :: Map.t()
+  defp hash(string) do
+    Enum.reduce(string, %{}, fn char, acc -> Map.update(acc, char, 1, &(&1 + 1)) end)
+  end
+end

elixir/anagram/mix.exs

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+defmodule Anagram.MixProject do
+  use Mix.Project
+
+  def project do
+    [
+      app: :anagram,
+      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

elixir/anagram/test/anagram_test.exs

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+defmodule AnagramTest do
+  use ExUnit.Case
+
+  test "no matches" do
+    matches = Anagram.match("diaper", ~w(hello world zombies pants))
+    assert matches == []
+  end
+
+  test "detects two anagrams" do
+    matches = Anagram.match("solemn", ~w(lemons cherry melons))
+    assert matches == ~w(lemons melons)
+  end
+
+  test "does not detect anagram subsets" do
+    matches = Anagram.match("good", ~w(dog goody))
+    assert matches == []
+  end
+
+  test "detects anagram" do
+    matches = Anagram.match("listen", ~w(enlists google inlets banana))
+    assert matches == ~w(inlets)
+  end
+
+  test "detects three anagrams" do
+    matches = Anagram.match("allergy", ~w(gallery ballerina regally clergy largely leading))
+    assert matches == ~w(gallery regally largely)
+  end
+
+  test "detects multiple anagrams with different case" do
+    matches = Anagram.match("nose", ~w(Eons ONES))
+    assert matches == ~w(Eons ONES)
+  end
+
+  test "does not detect non-anagrams with identical checksum" do
+    matches = Anagram.match("mass", ~w(last))
+    assert matches == []
+  end
+
+  test "detect anagrams case-insensitively" do
+    matches = Anagram.match("orchestra", ~w(cashregister Carthorse radishes))
+    assert matches == ~w(Carthorse)
+  end
+
+  test "detects anagrams using case-insensitive subject" do
+    matches = Anagram.match("Orchestra", ~w(cashregister carthorse radishes))
+    assert matches == ~w(carthorse)
+  end
+
+  test "detects anagrams using case-insensitive possible matches" do
+    matches = Anagram.match("orchestra", ~w(cashregister Carthorse radishes))
+    assert matches == ~w(Carthorse)
+  end
+
+  test "does not detect an anagram if the original word is repeated" do
+    matches = Anagram.match("go", ~w(goGoGO))
+    assert matches == []
+  end
+
+  test "anagrams must use all letters exactly once" do
+    matches = Anagram.match("tapper", ~w(patter))
+    assert matches == []
+  end
+
+  test "words are not anagrams of themselves" do
+    matches = Anagram.match("BANANA", ~w(BANANA))
+    assert matches == []
+  end
+
+  test "words are not anagrams of themselves even if letter case is partially different" do
+    matches = Anagram.match("BANANA", ~w(Banana))
+    assert matches == []
+  end
+
+  test "words are not anagrams of themselves even if letter case is completely different" do
+    matches = Anagram.match("BANANA", ~w(banana))
+    assert matches == []
+  end
+
+  test "words other than themselves can be anagrams" do
+    matches = Anagram.match("LISTEN", ~w(Silent LISTEN))
+    assert matches == ~w(Silent)
+  end
+
+  test "handles case of greek letters" do
+    matches = Anagram.match("ΑΒΓ", ~w(ΒΓΑ ΒΓΔ γβα αβγ))
+    assert matches == ~w(ΒΓΑ γβα)
+  end
+
+  test "different characters may have the same bytes" do
+    matches =
+      Anagram.match(
+        # binary representation: <<0x61, 0xE2, 0xAC, 0x82>>
+        "a⬂",
+        # binary representation: <<0xE2, 0x82, 0xAC, 0x61>>
+        ["€a"]
+      )
+
+    assert matches == []
+  end
+end

elixir/anagram/test/test_helper.exs

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+ExUnit.start()
+ExUnit.configure(exclude: :pending, trace: true)