Advent of Code 2019 - Day 8

bjorng · December 8, 2019, 5:56am

Note: This topic is to talk about Day 8 of the Advent of Code 2019.

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bjorng · December 8, 2019, 5:57am

Here is my solution.

qhwa · December 8, 2019, 6:16am

Here is mine.

aaronnamba · December 8, 2019, 6:25am

Day 8 solution. Fairly straightforward, not very efficient.

Also, damn that was one tricky captcha. I lost a minute or so trying to figure out whether there were any letters in there, then once I found some, I lost another minute because I read one of them wrong the first time.

KalvinHom · December 8, 2019, 8:45am

my solution
I used IO.ANSI to make the answer eaiser to read!

aaronnamba · December 8, 2019, 8:49am

Ah… I did not know about IO.ANSI, and forgot about reduce_while.

cblavier · December 8, 2019, 9:04am

It was much easier today! But it’s a good idea to have a more relaxing puzzle after yesterday’s crazy amplifier cluster

My code: https://github.com/cblavier/advent/blob/master/lib/2019/day8/part2.ex

I found it was easier for my brain to process layers in reverse order (from back to front). It’s also the first time ever I use Enum.zip.

sasajuric · December 8, 2019, 9:32am

My solution. Instead of printing chars directly, I converted the image into an iolist, which can be IO.puts-ed.

NobbZ · December 8, 2019, 10:21am

It was pretty straight forward today, took me about an hour on the wall, but I had to prepare my kids morning chocolate inbetween, so I’d guess it was about 30 to 45 minutes actual “CPU-time”

Though I really do not like those CAPTCHA style problems. We had one of those last year (or the year before that), and there already the community overall really disliked it, as it created additional hurdles for the visually impaired.

After the rant, now my code:

gitlab.com

NobbZ/aoc_ex/blob/master/lib/y2019/d8.ex

defmodule AocEx.Y2019.D8 do
  use AocEx.Boilerplate,
    transform: fn raw ->
      raw
      |> String.trim()
      |> String.graphemes()
      |> Enum.map(&String.to_integer/1)
    end

  @width 25
  @height 6

  def part1(input \\ processed()) do
    %{1 => ones, 2 => twos} =
      input
      |> Enum.chunk_every(@width * @height)
      |> Enum.min_by(fn layer -> layer |> Enum.filter(&(&1 == 0)) |> Enum.count() end)
      |> Enum.reduce(%{1 => 0, 2 => 0}, fn digit, acc -> Map.update(acc, digit, 0, &(&1 + 1)) end)

    ones * twos

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bossek · December 8, 2019, 10:57am

Day 08.

xfix · December 8, 2019, 11:01am

gitlab.com

KonradBorowski/advent_of_code_2019/blob/master/lib/day8.ex

defmodule AdventOfCode2019.Day8 do
  @moduledoc """
  Day 8 solutions
  """

  @doc """
  Solves the first riddle of day 8.

  ## Examples

      iex> File.read!("inputs/day8.txt") |> AdventOfCode2019.Day8.part1
      1072

  """
  def part1(input) do
    min = decode_layers(input) |> Enum.min_by(fn image -> Enum.count(image, &(&1 == "0")) end)
    Enum.count(min, &(&1 == "1")) * Enum.count(min, &(&1 == "2"))
  end

  @doc """

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Eh… Didn’t fully solve this in Elixir, because it’s not really worth it to implement OCR.

milli · December 8, 2019, 1:20pm

My solution, I liked today’s puzzle.

alvises · December 8, 2019, 1:22pm

Here’s mine, I’ve just put everything into part1 and part2 functions, piping the different steps. IO.ANSI colors made the message much more readable.

JEG2 · December 8, 2019, 9:54pm

My solution. It helped me to keep the layers one dimensional for as long as possible.

ferd · December 9, 2019, 2:16pm

Almost back up to date on Day 8: