AoC 2022 Day 2

Mix.install([:kino])

defmodule Utils do
  def split(line, sep \\ "") do
    String.split(line, sep, trim: true)
  end

  def split_all_lines(text, sep \\ "") do
    text
    |> String.split("\n", trim: true)
    |> Enum.map(&split(&1, sep))
  end

  def to_numbers(number) when is_binary(number) do
    String.to_integer(number)
  end

  def to_numbers(numbers) when is_list(numbers) do
    Enum.map(numbers, &to_numbers/1)
  end

  def to_matrix(text, sep \\ "") do
    text
    |> split_all_lines(sep)
    |> then(fn data ->
      for {row, r} <- Enum.with_index(data), {col, c} <- Enum.with_index(row) do
        {{r, c}, col}
      end
    end)
    |> Map.new()
  end
end

Setup

import Utils

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

text = Kino.Input.read(input)

data = split_all_lines(text, " ")

P1

for [<<op>>, <<me>>] <- data do
  op = op - ?A
  me = me - ?X

  choice = me + 1
  outcome = rem(me - op + 4, 3) * 3

  choice + outcome
end
|> Enum.sum()

P2

for [<<op>>, <<ot>>] <- data do
  op = op - ?A
  ot = ot - ?X

  outcome = ot * 3
  choice = rem(op + (ot - 1) + 3, 3) + 1

  choice + outcome
end
|> Enum.sum()