Advent of Code - Day 10

Mix.install(
  [
    {:kino_aoc, git: "https://github.com/ljgago/kino_aoc"}
  ],
  force: true
)

Section

{:ok, puzzle_input} = KinoAOC.download_puzzle("2022", "10", System.fetch_env!("LB_SESSION"))

input = """
addx 15
addx -11
addx 6
addx -3
addx 5
addx -1
addx -8
addx 13
addx 4
noop
addx -1
addx 5
addx -1
addx 5
addx -1
addx 5
addx -1
addx 5
addx -1
addx -35
addx 1
addx 24
addx -19
addx 1
addx 16
addx -11
noop
noop
addx 21
addx -15
noop
noop
addx -3
addx 9
addx 1
addx -3
addx 8
addx 1
addx 5
noop
noop
noop
noop
noop
addx -36
noop
addx 1
addx 7
noop
noop
noop
addx 2
addx 6
noop
noop
noop
noop
noop
addx 1
noop
noop
addx 7
addx 1
noop
addx -13
addx 13
addx 7
noop
addx 1
addx -33
noop
noop
noop
addx 2
noop
noop
noop
addx 8
noop
addx -1
addx 2
addx 1
noop
addx 17
addx -9
addx 1
addx 1
addx -3
addx 11
noop
noop
addx 1
noop
addx 1
noop
noop
addx -13
addx -19
addx 1
addx 3
addx 26
addx -30
addx 12
addx -1
addx 3
addx 1
noop
noop
noop
addx -9
addx 18
addx 1
addx 2
noop
noop
addx 9
noop
noop
noop
addx -1
addx 2
addx -37
addx 1
addx 3
noop
addx 15
addx -21
addx 22
addx -6
addx 1
noop
addx 2
addx 1
noop
addx -10
noop
noop
addx 20
addx 1
addx 2
addx 2
addx -6
addx -11
noop
noop
noop
"""

instructions =
  puzzle_input
  |> String.split("\n", trim: true)

defmodule Register do
  def read(instructions, register \\ [1])
  def read([], register), do: Enum.reverse(register)
  def read(["noop" | instructions], register), do: read(instructions, [hd(register) | register])

  def read(["addx " <> str_value | instructions], register) do
    value = String.to_integer(str_value)
    previous_state = hd(register)
    read(instructions, [previous_state + value | [previous_state | register]])
  end

  # Part 1
  def signal_strength(register) do
    register
    |> Enum.with_index()
    |> Enum.slice(19..length(register)//40)
    |> Enum.map(fn {x, i} -> x * (i + 1) end)
    |> Enum.sum()
  end

  # Part2

  def draw(register) do
    register
    |> Stream.chunk_every(40)
    |> Stream.map(fn line ->
      line
      |> Enum.with_index()
      |> Enum.map(&amp;draw_sprite/1)
      |> to_string()
    end)
    |> Enum.map(&amp;IO.puts/1)
  end

  def draw_sprite({r_value, position}) when position in [r_value - 1, r_value, r_value + 1],
    do: "#"

  def draw_sprite({_r_value, _position}), do: " "
end

Part 1

instructions
|> Register.read()
|> Register.signal_strength()

Part 2

instructions
|> Register.read()
|> Register.draw()