Day 4

Mix.install([
  {:kino, "~> 0.7.0"}
])

Section

input = Kino.Input.textarea("sections")

input
|> Kino.Input.read()
|> String.split("\n", trim: true)
|> Enum.count(fn sections ->
  [
    section1_lower_bounds,
    section1_upper_bounds,
    section2_lower_bounds,
    section2_upper_bounds
  ] =
    Regex.scan(~r/(\d+)-(\d+),(\d+)-(\d+)/, sections, capture: :all_but_first)
    |> List.flatten()
    |> Enum.map(&String.to_integer/1)

  [small_section, large_section] =
    [
      Range.new(section1_lower_bounds, section1_upper_bounds),
      Range.new(section2_lower_bounds, section2_upper_bounds)
    ]
    |> Enum.sort_by(&Range.size/1)

  Enum.member?(large_section, small_section.first) &&
    Enum.member?(large_section, small_section.last)
end)

input
|> Kino.Input.read()
|> String.split("\n", trim: true)
|> Enum.count(fn sections ->
  [
    section1_lower_bounds,
    section1_upper_bounds,
    section2_lower_bounds,
    section2_upper_bounds
  ] =
    Regex.scan(~r/(\d+)-(\d+),(\d+)-(\d+)/, sections, capture: :all_but_first)
    |> List.flatten()
    |> Enum.map(&String.to_integer/1)

  section1 = Range.new(section1_lower_bounds, section1_upper_bounds)
  section2 = Range.new(section2_lower_bounds, section2_upper_bounds)

  section1 |> Range.disjoint?(section2) |> Kernel.not()
end)