DEV Community

Caleb Weeks
Caleb Weeks

Posted on • Updated on • Originally published at sethcalebweeks.com

Advent of Code Day 4

#adventofcode #elixir

Links

Highlights

  • Nothing too extraordinary with today's problem. For the second part, I started by only checking to see if either endpoint of one elf was within the endpoints of the other elf. Honestly, I still can't figure out why this didn't work, and I had to do the same check in the other direction. Maybe it will come to me at some point today. 
defmodule Day04 do
  use AOC

  def part1 do
    input(4)
    ~> String.split("\n")
    ~> Enum.map(fn pair ->
      ends = Regex.named_captures(~r/(?<l1>.*)-(?<h1>.*),(?<l2>.*)-(?<h2>.*)/, pair)
      ~> Map.new(fn {key, value} -> {String.to_atom(key), String.to_integer(value)} end)
      (ends.l1 <= ends.l2 && ends.h1 >= ends.h2) ||
      (ends.l2 <= ends.l1 && ends.h2 >= ends.h1)
    end)
    ~> Enum.count(&Function.identity(&1))
  end

  def part2 do
    input(4)
    ~> String.split("\n")
    ~> Enum.map(fn pair ->
      ends = Regex.named_captures(~r/(?<l1>.*)-(?<h1>.*),(?<l2>.*)-(?<h2>.*)/, pair)
      ~> Map.new(fn {key, value} -> {String.to_atom(key), String.to_integer(value)} end)
      (ends.l1 >= ends.l2 && ends.l1 <= ends.h2) ||
      (ends.h1 >= ends.l2 && ends.h1 <= ends.h2) ||
      (ends.l2 >= ends.l1 && ends.l2 <= ends.h1) ||
      (ends.h2 >= ends.l1 && ends.h2 <= ends.h1)
    end)
    ~> Enum.count(&Function.identity(&1))
  end

end
Enter fullscreen mode Exit fullscreen mode

Top comments (0)

Read next

mostafa_abbac_bc9ecdd4dbc profile image

HyperTAG, an Open-Source Telegram Bot That Summarizes Links & YouTube Videos with AI, and Also Does a Lot More!

mostafa abbac -

nabata profile image

Replacing Only the Background of an Image with AI Generation Using the Stable Diffusion Web API

nabata -

lithephp profile image

Organizing Your Routes Modularly and Automatically in Lithe

Lithe -

zenx5 profile image

¿Cómo definir el estado?

Octavio Martinez -