From f0d0aa0597a7e19f994da6d015628f721f5ba08f Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Sebastian=20G=C3=B6ttschkes?= Date: Sat, 9 Dec 2023 19:37:56 +0100 Subject: [PATCH] Implement roman-numerals in Elixir --- elixir/roman-numerals/.formatter.exs | 4 + elixir/roman-numerals/.gitignore | 24 ++++ elixir/roman-numerals/HELP.md | 75 +++++++++++++ elixir/roman-numerals/README.md | 72 ++++++++++++ elixir/roman-numerals/lib/roman_numerals.ex | 48 ++++++++ elixir/roman-numerals/mix.exs | 28 +++++ .../test/roman_numerals_test.exs | 103 ++++++++++++++++++ elixir/roman-numerals/test/test_helper.exs | 2 + 8 files changed, 356 insertions(+) create mode 100644 elixir/roman-numerals/.formatter.exs create mode 100644 elixir/roman-numerals/.gitignore create mode 100644 elixir/roman-numerals/HELP.md create mode 100644 elixir/roman-numerals/README.md create mode 100644 elixir/roman-numerals/lib/roman_numerals.ex create mode 100644 elixir/roman-numerals/mix.exs create mode 100644 elixir/roman-numerals/test/roman_numerals_test.exs create mode 100644 elixir/roman-numerals/test/test_helper.exs diff --git a/elixir/roman-numerals/.formatter.exs b/elixir/roman-numerals/.formatter.exs new file mode 100644 index 0000000..d2cda26 --- /dev/null +++ b/elixir/roman-numerals/.formatter.exs @@ -0,0 +1,4 @@ +# Used by "mix format" +[ + inputs: ["{mix,.formatter}.exs", "{config,lib,test}/**/*.{ex,exs}"] +] diff --git a/elixir/roman-numerals/.gitignore b/elixir/roman-numerals/.gitignore new file mode 100644 index 0000000..2a676eb --- /dev/null +++ b/elixir/roman-numerals/.gitignore @@ -0,0 +1,24 @@ +# 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"). +roman_numerals-*.tar + diff --git a/elixir/roman-numerals/HELP.md b/elixir/roman-numerals/HELP.md new file mode 100644 index 0000000..5fabbf9 --- /dev/null +++ b/elixir/roman-numerals/HELP.md @@ -0,0 +1,75 @@ +# 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/.exs:LINENUM` - runs only a single test, the test from `.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/roman_numerals.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. \ No newline at end of file diff --git a/elixir/roman-numerals/README.md b/elixir/roman-numerals/README.md new file mode 100644 index 0000000..9b65ff5 --- /dev/null +++ b/elixir/roman-numerals/README.md @@ -0,0 +1,72 @@ +# Roman Numerals + +Welcome to Roman Numerals on Exercism's Elixir Track. +If you need help running the tests or submitting your code, check out `HELP.md`. + +## Instructions + +Write a function to convert from normal numbers to Roman Numerals. + +The Romans were a clever bunch. +They conquered most of Europe and ruled it for hundreds of years. +They invented concrete and straight roads and even bikinis. +One thing they never discovered though was the number zero. +This made writing and dating extensive histories of their exploits slightly more challenging, but the system of numbers they came up with is still in use today. +For example the BBC uses Roman numerals to date their programs. + +The Romans wrote numbers using letters - I, V, X, L, C, D, M. +(notice these letters have lots of straight lines and are hence easy to hack into stone tablets). + +```text + 1 => I +10 => X + 7 => VII +``` + +The maximum number supported by this notation is 3,999. +(The Romans themselves didn't tend to go any higher) + +Wikipedia says: Modern Roman numerals ... are written by expressing each digit separately starting with the left most digit and skipping any digit with a value of zero. + +To see this in practice, consider the example of 1990. + +In Roman numerals 1990 is MCMXC: + +1000=M +900=CM +90=XC + +2008 is written as MMVIII: + +2000=MM +8=VIII + +Learn more about [Roman numerals on Wikipedia][roman-numerals]. + +[roman-numerals]: https://wiki.imperivm-romanvm.com/wiki/Roman_Numerals + +## Source + +### Created by + +- @rubysolo + +### Contributed to by + +- @andrewsardone +- @angelikatyborska +- @cetinajero +- @Cohen-Carlisle +- @dalexj +- @devonestes +- @jinyeow +- @lpil +- @neenjaw +- @parkerl +- @sotojuan +- @Teapane +- @waiting-for-dev + +### Based on + +The Roman Numeral Kata - https://codingdojo.org/kata/RomanNumerals/ \ No newline at end of file diff --git a/elixir/roman-numerals/lib/roman_numerals.ex b/elixir/roman-numerals/lib/roman_numerals.ex new file mode 100644 index 0000000..5658cc4 --- /dev/null +++ b/elixir/roman-numerals/lib/roman_numerals.ex @@ -0,0 +1,48 @@ +defmodule RomanNumerals do + @doc """ + Convert the number to a roman number. + """ + @spec numeral(pos_integer) :: String.t() + def numeral(number) do + result = + [1000, 500, 100, 50, 10, 5, 1] + |> Enum.reduce({"", number}, fn cur, {result, num} -> + case round(:math.floor(num / cur)) do + 0 -> + {result, num} + + amount -> + result = + result <> + (Range.to_list(1..amount) |> Enum.map(fn _ -> to_literal(cur) end) |> Enum.join()) + + {result, num - amount * cur} + end + end) + |> then(fn {result, _} -> result end) + + Enum.reduce( + [ + {"DCCCC", "CM"}, + {"CCCC", "CD"}, + {"LXXXX", "XC"}, + {"XXXX", "XL"}, + {"VIIII", "IX"}, + {"IIII", "IV"} + ], + result, + fn {src, dest}, acc -> + String.replace(acc, src, dest) + end + ) + end + + defp to_literal(1), do: "I" + defp to_literal(5), do: "V" + defp to_literal(10), do: "X" + defp to_literal(50), do: "L" + defp to_literal(100), do: "C" + defp to_literal(500), do: "D" + defp to_literal(1000), do: "M" + defp to_literal(_), do: "" +end diff --git a/elixir/roman-numerals/mix.exs b/elixir/roman-numerals/mix.exs new file mode 100644 index 0000000..33f5ed5 --- /dev/null +++ b/elixir/roman-numerals/mix.exs @@ -0,0 +1,28 @@ +defmodule RomanNumerals.MixProject do + use Mix.Project + + def project do + [ + app: :roman_numerals, + 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 diff --git a/elixir/roman-numerals/test/roman_numerals_test.exs b/elixir/roman-numerals/test/roman_numerals_test.exs new file mode 100644 index 0000000..b3332f8 --- /dev/null +++ b/elixir/roman-numerals/test/roman_numerals_test.exs @@ -0,0 +1,103 @@ +defmodule RomanNumeralsTest do + use ExUnit.Case + + test "1" do + assert RomanNumerals.numeral(1) == "I" + end + + test "2" do + assert RomanNumerals.numeral(2) == "II" + end + + test "3" do + assert RomanNumerals.numeral(3) == "III" + end + + test "4" do + assert RomanNumerals.numeral(4) == "IV" + end + + test "5" do + assert RomanNumerals.numeral(5) == "V" + end + + test "6" do + assert RomanNumerals.numeral(6) == "VI" + end + + test "9" do + assert RomanNumerals.numeral(9) == "IX" + end + + test "27" do + assert RomanNumerals.numeral(27) == "XXVII" + end + + test "48" do + assert RomanNumerals.numeral(48) == "XLVIII" + end + + test "59" do + assert RomanNumerals.numeral(59) == "LIX" + end + + test "93" do + assert RomanNumerals.numeral(93) == "XCIII" + end + + test "141" do + assert RomanNumerals.numeral(141) == "CXLI" + end + + test "163" do + assert RomanNumerals.numeral(163) == "CLXIII" + end + + test "402" do + assert RomanNumerals.numeral(402) == "CDII" + end + + test "575" do + assert RomanNumerals.numeral(575) == "DLXXV" + end + + test "911" do + assert RomanNumerals.numeral(911) == "CMXI" + end + + test "1024" do + assert RomanNumerals.numeral(1024) == "MXXIV" + end + + test "3000" do + assert RomanNumerals.numeral(3000) == "MMM" + end + + test "16" do + assert RomanNumerals.numeral(16) == "XVI" + end + + test "66" do + assert RomanNumerals.numeral(66) == "LXVI" + end + + test "166" do + assert RomanNumerals.numeral(166) == "CLXVI" + end + + test "666" do + assert RomanNumerals.numeral(666) == "DCLXVI" + end + + test "1666" do + assert RomanNumerals.numeral(1666) == "MDCLXVI" + end + + test "3001" do + assert RomanNumerals.numeral(3001) == "MMMI" + end + + test "3999" do + assert RomanNumerals.numeral(3999) == "MMMCMXCIX" + end +end diff --git a/elixir/roman-numerals/test/test_helper.exs b/elixir/roman-numerals/test/test_helper.exs new file mode 100644 index 0000000..35fc5bf --- /dev/null +++ b/elixir/roman-numerals/test/test_helper.exs @@ -0,0 +1,2 @@ +ExUnit.start() +ExUnit.configure(exclude: :pending, trace: true)