Caleb Weeks

Posted on Dec 2, 2022 • Updated on Dec 6, 2022 • Originally published at sethcalebweeks.com

Advent of Code Day 2

#adventofcode #elixir

Highlights

It feels really naive to simply hard code the total score for each combination. The mental load of thinking through who would win and encoding that in a smart way would have taken just as long if not longer than just writing down the correct score for each combination.
This is where pattern matching works really well. Just match each combination with the correspoding score.

defmodule Day02 do
  use AOC

  def part1 do
    input(2)
    ~> String.split("\n")
    ~> Enum.map(fn round ->
      case round ~> String.split(" ") do
        ["A", "X"] -> 4
        ["B", "X"] -> 1
        ["C", "X"] -> 7
        ["A", "Y"] -> 8
        ["B", "Y"] -> 5
        ["C", "Y"] -> 2
        ["A", "Z"] -> 3
        ["B", "Z"] -> 9
        ["C", "Z"] -> 6
      end
    end)
    ~> Enum.sum()
  end

  def part2 do
    input(2)
    ~> String.split("\n")
    ~> Enum.map(fn round ->
      case round ~> String.split(" ") do
        ["A", "X"] -> 3
        ["B", "X"] -> 1
        ["C", "X"] -> 2
        ["A", "Y"] -> 4
        ["B", "Y"] -> 5
        ["C", "Y"] -> 6
        ["A", "Z"] -> 8
        ["B", "Z"] -> 9
        ["C", "Z"] -> 7
      end
    end)
    ~> Enum.sum()
  end

end

Top comments (1)

Caleb Weeks • Dec 2 '22

I probably thought I could do something clever with assigning values to the letters somehow, so that's why I split out the line into the two letters. Turns out I may as well just be matching on the original line instead of an array of the two letters.

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