AoC - Day6

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

Setup

{:ok, data} = KinoAOC.download_puzzle("2022", "6", System.fetch_env!("LB_AOC_SECRET"))

Solve

defmodule Day6 do
  def solve(data) do
    chars = data |> String.trim() |> String.graphemes()

    {tune(chars, 4) + 4, tune(chars, 14) + 14}
  end

  # def tune(data, win) do
  #   data
  #   |> Enum.chunk_every(win, 1)
  #   |> Enum.map(&MapSet.new/1)
  #   |> Enum.map(&MapSet.size/1)
  #   |> Enum.reduce_while(win, fn seq, acc ->
  #     if seq == win, do: {:halt, acc}, else: {:cont, acc + 1}
  #   end)
  # end

  # simpler version
  def tune(data, win) do
    data
    |> Enum.chunk_every(win, 1)
    |> Enum.map(&uniq_size/1)
    |> Enum.find_index(&(&1 == win))
  end

  def uniq_size(chunk), do: chunk |> MapSet.new() |> MapSet.size()
end

# {1625, 2250}
Day6.solve(data)

Check

ExUnit.start(autorun: false)

defmodule AoCTest do
  use ExUnit.Case, async: false

  tests = [
    {"mjqjpqmgbljsphdztnvjfqwrcgsmlb", {7, 19}},
    {"bvwbjplbgvbhsrlpgdmjqwftvncz", {5, 23}},
    {"nppdvjthqldpwncqszvftbrmjlhg", {6, 23}},
    {"nznrnfrfntjfmvfwmzdfjlvtqnbhcprsg", {10, 29}},
    {"zcfzfwzzqfrljwzlrfnpqdbhtmscgvjw", {11, 26}}
  ]

  for {{tdata, res}, ind} <- Enum.with_index(tests) do
    test "solves test cases #{ind}" do
      assert unquote(res) = Day6.solve(unquote(tdata))
    end
  end
end

ExUnit.run()