Day 04

Section

defmodule Day04 do
  def part1(input_path) do
    input_path
    |> File.read!()
    |> String.split(~r/\D+/m, global: true, trim: true)
    |> Stream.map(&String.to_integer/1)
    |> Stream.chunk_every(4)
    |> Enum.count(fn [a1, b1, a2, b2] ->
      (a1 <= a2 and b1 >= b2) or
        (a1 >= a2 and b1 <= b2)
    end)
  end

  def part2(input_path) do
    input_path
    |> File.read!()
    |> String.split(~r/\D+/m, global: true, trim: true)
    |> Stream.map(&String.to_integer/1)
    |> Stream.chunk_every(4)
    |> Enum.count(fn [a1, b1, a2, b2] ->
      a1 <= b2 and a2 <= b1
    end)
  end
end

input_file = "#{__DIR__}/day04.txt"

Day04.part1(input_file)