2022 day 01 in Elixir

Author: sanderploegsma

2022/elixir/.formatter.exs

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

2022/elixir/.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").
+advent_of_code_2022-*.tar
+
+# Temporary files, for example, from tests.
+/tmp/

2022/elixir/README.md

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+# AdventOfCode2022
+
+Solve exercises using [lib/mix/tasks/solve.ex](./lib/mix/tasks/solve.ex):
+
+```sh
+mix solve day01
+```

2022/elixir/lib/day01.ex

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+defmodule Day01 do
+  @input File.read!("../input/day01.txt")
+
+  def part_one(input \\ @input) do
+    parse_input(input)
+    |> Enum.max()
+  end
+
+  def part_two(input \\ @input) do
+    parse_input(input)
+    |> Enum.sort(:desc)
+    |> Enum.take(3)
+    |> Enum.sum()
+  end
+
+  defp parse_input(input) do
+    input
+    |> String.trim()
+    |> String.split("\n\n")
+    |> Enum.map(fn block ->
+      block
+      |> String.split("\n")
+      |> Enum.map(&String.to_integer/1)
+      |> Enum.sum()
+    end)
+  end
+end

2022/elixir/lib/mix/tasks/solve.ex

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+defmodule Mix.Tasks.Solve do
+  use Mix.Task
+
+  def run([module | _]) do
+    apply(String.to_existing_atom("Elixir.#{String.capitalize(module)}"), :part_one, [])
+    |> IO.inspect(label: "Part one")
+
+    apply(String.to_existing_atom("Elixir.#{String.capitalize(module)}"), :part_two, [])
+    |> IO.inspect(label: "Part two")
+  end
+end

2022/elixir/mix.exs

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+defmodule AdventOfCode2022.MixProject do
+  use Mix.Project
+
+  def project do
+    [
+      app: :advent_of_code_2022,
+      version: "0.1.0",
+      elixir: "~> 1.15",
+      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

2022/elixir/test/day01_test.exs

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+defmodule Day01Test do
+  use ExUnit.Case
+
+  @example_input """
+  1000
+  2000
+  3000
+
+  4000
+
+  5000
+  6000
+
+  7000
+  8000
+  9000
+
+  10000
+  """
+
+  test "part one", do: assert(Day01.part_one(@example_input) == 24000)
+  test "part two", do: assert(Day01.part_two(@example_input) == 45000)
+end

2022/elixir/test/test_helper.exs

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+ExUnit.start()
+ExUnit.configure(trace: true)