AoC 2022 Day 10

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, " ")
  |> Enum.map(fn
    ["noop"] -> :noop
    ["addx", n] -> {:addx, String.to_integer(n)}
  end)

P1

defmodule P1 do
  def solve(input) do
    input
    |> Enum.reduce({[], 1}, fn
      :noop, {acc, s} -> {[[s] | acc], s}
      {:addx, n}, {acc, s} -> {[[s, s] | acc], s + n}
    end)
    |> elem(0)
    |> Enum.reverse()
    |> List.flatten()
  end
end

result = P1.solve(data)
Enum.map([20, 60, 100, 140, 180, 220], &(Enum.at(result, &1 - 1) * &1)) |> Enum.sum()

P2

for {s, i} <- Enum.with_index(result) do
  if (s - rem(i, 40)) in [-1, 0, 1] do
    "#"
  else
    " "
  end
end
|> Enum.chunk_every(40)
|> Enum.each(&amp;IO.puts/1)