day 1

README.md

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+# Advent of Code 2024

elixir/.formatter.exs

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

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_2024-*.tar
+
+# Temporary files, for example, from tests.
+/tmp/

elixir/README.md

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+# AdventOfCode2024
+
+**TODO: Add description**
+
+## Installation
+
+If [available in Hex](https://hex.pm/docs/publish), the package can be installed
+by adding `advent_of_code_2024` to your list of dependencies in `mix.exs`:
+
+```elixir
+def deps do
+  [
+    {:advent_of_code_2024, "~> 0.1.0"}
+  ]
+end
+```
+
+Documentation can be generated with [ExDoc](https://github.com/elixir-lang/ex_doc)
+and published on [HexDocs](https://hexdocs.pm). Once published, the docs can
+be found at <https://hexdocs.pm/advent_of_code_2024>.
+

elixir/lib/day1.ex

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+defmodule Day1 do
+  def part1(file_path) do
+    file_path
+    |> File.read!()
+    |> String.split("\n")
+    |> Enum.map(&String.split/1)
+    |> Enum.filter(fn list -> length(list) == 2 end)
+    |> Enum.map(fn [a, b] -> {String.to_integer(a), String.to_integer(b)} end)
+    |> Enum.unzip()
+    |> Tuple.to_list()
+    |> Enum.map(&Enum.sort/1)
+    |> Enum.zip()
+    |> Enum.map(fn {a, b} -> abs(a - b) end)
+    |> Enum.sum()
+  end
+
+  def part2(file_path) do
+    file_path
+    |> File.read!()
+    |> String.split("\n")
+    |> Enum.map(&String.split/1)
+    |> Enum.filter(fn list -> length(list) == 2 end)
+    |> Enum.map(fn [a, b] -> {String.to_integer(a), String.to_integer(b)} end)
+    |> Enum.unzip()
+    |> Tuple.to_list()
+    |> Enum.map(&Enum.sort/1)
+    |> (fn [list1, list2] -> {list1, Enum.frequencies(list2)} end).()
+    |> (fn {list1, freqs} ->
+          list1
+          |> Enum.map(&{&1, Map.get(freqs, &1, 0)})
+          |> Enum.filter(fn {_, count} -> count != 0 end)
+          |> Enum.map(fn {value, count} -> value * count end)
+        end).()
+    |> Enum.sum()
+  end
+end

elixir/lib/day2.ex

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+defmodule Day2 do
+  def part1(file_path) do
+    file_path
+    |> File.read!()
+    |> String.split("\n")
+    |> Enum.map(&String.split/1)
+  end
+
+  def part2(file_path) do
+    file_path
+    |> File.read!()
+    |> String.split("\n")
+    |> Enum.map(&String.split/1)
+  end
+end

elixir/mix.exs

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+defmodule AdventOfCode2024.MixProject do
+  use Mix.Project
+
+  def project do
+    [
+      app: :advent_of_code_2024,
+      version: "0.1.0",
+      elixir: "~> 1.17",
+      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/test/advent_of_code2024_test.exs

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+defmodule AdventOfCode2024Test do
+  use ExUnit.Case
+  doctest Day1
+
+  test "answers question 1.1" do
+    Day1.part1("test/1/input")
+  end
+
+  test "answers question 1.2" do
+    Day1.part2("test/1/input")
+  end
+
+  doctest Day2
+
+  test "answers question 2.1" do
+    Day2.part1("test/1/input")
+  end
+
+  test "answers question 2.2" do
+    Day2.part2("test/1/input")
+  end
+end

elixir/test/test_helper.exs

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+ExUnit.start()