Solve 242 - Valid Anagram (#8)

Author: terenceponce

README.md

@@ -10,3 +10,4 @@ This is a monorepo containing my solutions to LeetCode problems written in vario
 
 - 1 - Two Sum - [Notes](notes/0001_two_sum.md) | [Elixir](elixir/lib/solutions/0001_two_sum/two_sum.ex) | [Ruby](ruby/lib/solutions/0001_two_sum/two_sum.rb)
 - 217 - Contains Duplicate - [Notes](notes/0217_contains_duplicate.md) | [Elixir](elixir/lib/solutions/0217_contains_duplicate/contains_duplicate.ex) | [Ruby](ruby/lib/solutions/0217_contains_duplicate/contains_duplicate.rb)
+- 242 - Valid Anagram - [Notes](notes/0242_valid_anagram.md) | [Elixir](elixir/lib/solutions/0242_valid_anagram/valid_anagram.ex) | [Ruby](ruby/lib/solutions/0242_valid_anagram/valid_anagram.rb)

elixir/lib/solutions/0242_valid_anagram/valid_anagram.ex

@@ -0,0 +1,14 @@
+defmodule LeetCode.Solutions.ValidAnagram do
+  @moduledoc false
+
+  @spec call(s :: String.t(), t :: String.t()) :: boolean
+  def call(s, t) do
+    anagram?(s) == anagram?(t)
+  end
+
+  defp anagram?(word) do
+    word
+    |> String.graphemes()
+    |> Enum.sort()
+  end
+end

elixir/test/solutions/0242_valid_anagram/valid_anagram_test.exs

@@ -0,0 +1,13 @@
+defmodule LeetCode.Solutions.ValidAnagramTest do
+  use ExUnit.Case, async: true
+
+  alias LeetCode.Solutions.ValidAnagram
+
+  test "Case 1 works" do
+    assert ValidAnagram.call("anagram", "nagaram") == true
+  end
+
+  test "Case 2 works" do
+    assert ValidAnagram.call("rat", "car") == false
+  end
+end

notes/0242_valid_anagram.md

@@ -0,0 +1,59 @@
+# Valid Anagram
+
+**Link to Problem**: https://leetcode.com/problems/valid-anagram
+
+## Solutions
+
+- [Elixir](../elixir/lib/solutions/0242_valid_anagram/valid_anagram.ex)
+- [Ruby](../ruby/lib/solutions/0242_valid_anagram/valid_anagram.rb)
+
+## Description
+
+Given two strings `s` and `t`, return `true` if `t` is an anagram of `s`, and `false` otherwise.
+
+An **Anagram** is a word or phrase formed by rearranging the letters of a different word or phrase, typically using all the original letters exactly once.
+
+## Examples
+
+### Example 1
+
+```
+Input: s = "anagram", t = "nagaram"
+Output: true
+```
+
+### Example 2
+
+```
+Input: s = "rat", t = "car"
+Output: false
+```
+
+## Approach
+
+The trick is to sort the words by their characters and compare the two.
+
+## Thoughts
+
+The solutions for both Elixir and Ruby look about the same, but Elixir is bit more verbose since it's
+a functional language.
+
+The Elixir solution is a redo from my previous attempt at it in my [old LeetCode repo](https://github.com/terenceponce/leetcode-elixir/tree/main/lib/solutions/00242_valid_anagram).
+I have a longer write up about this problem in the old repo, but I won't copy it over here since that
+feeling of solving it for the first time is gone now.
+
+The Ruby solution is new though and it's the reason why I rewrote my solution for Elixir. Going a bit
+off-topic here, but the reason why I had to make a new repo is so I can practice LeetCode in other
+languages.
+
+As for the reason why I want to practice in other languages, I applied to Amazon recently and I had a
+rude awakening when I encountered their Online Assessment. It was done through HackerRank and while I
+was able to verify that HackerRank does support Elixir, apparently, companies can restrict the languages
+available.
+
+Unfortunately, Elixir was not part of the available languages to use for the assessment, so I had to
+scramble and figure out how to do LeetCode in Ruby. I haven't done the assessment yet, but I'm pretty
+sure I'll fail it because of the fact that I have done all of my preparations exclusively in Elixir.
+
+Regardless, I think it's a good exercise for me to practice LeetCode using both OOP and Functional
+Programming, so starting this repo is already worth it.

ruby/lib/solutions/0242_valid_anagram/valid_anagram.rb

@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+def anagram?(word1, word2)
+  word1.chars.sort == word2.chars.sort
+end

ruby/test/solutions/0242_valid_anagram/valid_anagram_test.rb

@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+require 'test_helper'
+require_relative '../../../lib/solutions/0242_valid_anagram/valid_anagram'
+
+class ValidAnagramTest < Minitest::Test
+  def test_case_1_works
+    assert anagram?('anagram', 'nagaram')
+  end
+
+  def test_case_2_works
+    refute anagram?('rat', 'car')
+  end
+end