2023 Day 14

Mix.install([
  {:req, "~> 0.4.5"},
  {:vega_lite, "~> 0.1.8"},
  {:kino_vega_lite, "~> 0.1.11"}
])

alias VegaLite, as: Vl

defmodule AOC do
  @aoc_session System.fetch_env!("LB_AOC_SESSION")

  def day(day, year) when day in 1..25 do
    headers = [cookie: "session=#{@aoc_session}"]
    req = Req.new(base_url: "https://adventofcode.com/#{year}/day/#{day}", headers: headers)
    input = Req.get!(req, url: "/input").body

    if input =~ "Please don't repeatedly request this endpoint before it unlocks",
      do: {:error, "Day #{day} hasn't been unlocked yet"},
      else: {:ok, %{req: req, input: input}}
  end

  def submit(answer, %{req: req}, part \\ :part_1) when part in [:part_1, :part_2] do
    part = if part == :part_2, do: 2, else: 1

    if !part_already_completed?(part, req) do
      body = Req.post!(req, url: "/answer", form: [level: part, answer: answer]).body

      cond do
        body =~ "That's the right answer" -> {:correct, answer}
        body =~ "your answer is too low" -> {:too_low, answer}
        body =~ "your answer is too high" -> {:too_high, answer}
        :else -> {:incorrect, answer}
      end
    else
      {:already_completed_part, answer}
    end
  end

  defp part_already_completed?(part, req) do
    body = Req.get!(req).body

    cond do
      body =~ "Both parts of this puzzle are complete!" -> true
      body =~ "The first half of this puzzle is complete!" -> part == 1
      :else -> false
    end
  end

  def nums(str) do
    Regex.scan(~r/\d+/, str) |> Enum.map(fn [x] -> String.to_integer(x) end)
  end
end

{:ok, day} = AOC.day(14, 2023)

Part 1

test_input = """
O....#....
O.OO#....#
.....##...
OO.#O....O
.O.....O#.
O.#..O.#.#
..O..#O..O
.......O..
#....###..
#OO..#....
"""

defmodule P1 do
  def solve(input) do
    input
    |> String.split("\n", trim: true)
    |> columns()
    |> slide(:north)
    |> Enum.sum()
  end

  def columns(rows) do
    rows
    |> Enum.map(&String.graphemes/1)
    |> Enum.zip()
    |> Enum.map(&(&1 |> Tuple.to_list() |> Enum.join() |> String.reverse()))
  end

  @doc """
    iex> P1.slide(["##..O.O.OO"], :north)
    [34]

    iex> P1.slide(["O..O.#O.#."], :north)
    [17]
  """
  def slide(grid, :north) do
    grid
    |> Enum.map(fn str ->
      str = str <> "#"
      blocks = Regex.scan(~r/#/, str, return: :index) |> Enum.map(fn [{i, _}] -> i end)

      str
      |> String.split("#")
      |> Enum.zip(blocks)
      |> Enum.map(fn {str, x} ->
        {str |> String.to_charlist() |> Enum.frequencies() |> Map.get(?O, 0), x}
      end)
      |> Enum.reject(fn {o, _} -> o == 0 end)
      |> Enum.map(fn {n, i} -> Enum.sum(i..(i - n + 1)) end)
      |> Enum.sum()

      # |> dbg()
    end)
  end

  def load(grid, :north) do
    grid
    |> Enum.filter(fn {_, v} -> v == "O" end)
    |> Enum.map(fn {{_x, y}, "O"} -> y end)
    |> Enum.sum()
  end
end

# test_input |> P1.solve()
day.input |> P1.solve() |> AOC.submit(day)

Part 2

defmodule P2 do
  def solve(input) do
    input
  end
end

test_input |> P2.solve()
# day.input |> P2.solve()