Solve 2021 Day 8 part 1 in elixir

2021/Day8/Elixir/seven_segment_search.ex

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+ExUnit.start()
+
+defmodule SevenSegmentSearch do
+  def load_file(path) do
+    File.read!(path)
+    |> String.split("\n", trim: true)
+  end
+
+  def parse_input(lines) do
+    lines
+    |> Enum.map(fn line ->
+      {signals, output_values} =
+        String.split(line, "|", trim: true)
+        |> Enum.map(fn part -> String.split(part, " ", trim: true) end)
+        |> List.to_tuple()
+    end)
+  end
+
+  @spec find_unique([String], [String]) :: [String]
+  def find_unique(signals, output_values) do
+    unique_signal_lengths =
+      signals
+      |> Enum.map(&String.length/1)
+      |> Enum.frequencies()
+      |> Enum.filter(fn {_, occurences} -> occurences == 1 end)
+      |> Enum.map(&elem(&1, 0))
+
+    Enum.filter(output_values, fn value ->
+      Enum.member?(unique_signal_lengths, String.length(value))
+    end)
+  end
+
+  @spec first() :: Integer
+  def first() do
+    inputs =
+      load_file("../input.txt")
+      |> parse_input()
+
+    Enum.map(inputs, fn {signals, output_values} -> find_unique(signals, output_values) end)
+    |> List.flatten()
+    |> Enum.count()
+  end
+
+  @spec second() :: Integer
+  def second() do
+    :second
+  end
+end
+
+defmodule SevenSegmentSearchTest do
+  use ExUnit.Case
+
+  describe "find_unique/2" do
+    test "Example" do
+      signals = [
+        "be",
+        "cfbegad",
+        "cbdgef",
+        "fgaecd",
+        "cgeb",
+        "fdcge",
+        "agebfd",
+        "fecdb",
+        "fabcd",
+        "edb"
+      ]
+
+      output_values = ["fdgacbe", "cefdb", "cefbgd", "gcbe"]
+
+      expected_result = ["fdgacbe", "gcbe"]
+      assert SevenSegmentSearch.find_unique(signals, output_values) == expected_result
+    end
+  end
+end

2021/Day8/test.txt

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+be cfbegad cbdgef fgaecd cgeb fdcge agebfd fecdb fabcd edb | fdgacbe cefdb cefbgd gcbe
+edbfga begcd cbg gc gcadebf fbgde acbgfd abcde gfcbed gfec | fcgedb cgb dgebacf gc
+fgaebd cg bdaec gdafb agbcfd gdcbef bgcad gfac gcb cdgabef | cg cg fdcagb cbg
+fbegcd cbd adcefb dageb afcb bc aefdc ecdab fgdeca fcdbega | efabcd cedba gadfec cb
+aecbfdg fbg gf bafeg dbefa fcge gcbea fcaegb dgceab fcbdga | gecf egdcabf bgf bfgea
+fgeab ca afcebg bdacfeg cfaedg gcfdb baec bfadeg bafgc acf | gebdcfa ecba ca fadegcb
+dbcfg fgd bdegcaf fgec aegbdf ecdfab fbedc dacgb gdcebf gf | cefg dcbef fcge gbcadfe
+bdfegc cbegaf gecbf dfcage bdacg ed bedf ced adcbefg gebcd | ed bcgafe cdgba cbgef
+egadfb cdbfeg cegd fecab cgb gbdefca cg fgcdab egfdb bfceg | gbdfcae bgc cg cgb
+gcafb gcf dcaebfg ecagb gf abcdeg gaef cafbge fdbac fegbdc | fgae cfgab fg bagce