Advent of code day 07

Mix.install([
  {:kino, "~> 0.5.0"}
])

Setup input

example = Kino.Input.textarea("Please paste your input example:")

input = Kino.Input.textarea("Please paste your real input:")

Part 01

letter_map = %{"T" => "A", "J" => "B", "Q" => "C", "K" => "D", "A" => "E"}

classify = fn hand ->
  counts = String.split(hand, "", trim: true) |> Enum.frequencies() |> Map.values()
  cond do
    5 in counts -> 6
    4 in counts -> 5
    3 in counts and 2 in counts -> 4
    3 in counts -> 3
    Enum.count(counts, fn c -> c == 2 end) == 2 -> 2  
    2 in counts -> 1 
    true -> 0 
  end
end

score = fn {hand, _bid} ->
  alph =
    String.split(hand, "", trim: true)
    |> Enum.map(fn letter -> Map.get(letter_map, letter, letter) end)
    |> Enum.join("")

  {classify.(hand), alph}
end

example
|> Kino.Input.read()
|> String.split(["\n", " "], trim: true)
|> Enum.chunk_every(2)
|> Enum.map(fn [card, bid | _] ->
  {card, String.to_integer(bid)}
end)
|> Enum.sort_by(fn hand_bid -> score.(hand_bid) end)
|> Enum.reduce({0, 1}, fn {_, bid}, {total, i} ->
  {total + (i * bid), i + 1}
end)

Part 02

letter_map = %{"T" => "A", "J" => ".", "Q" => "C", "K" => "D", "A" => "E"}

classify = fn hand ->
  counts = String.split(hand, "", trim: true) |> Enum.frequencies() |> Map.values()

  cond do
    5 in counts -> 6
    4 in counts -> 5
    3 in counts and 2 in counts -> 4
    3 in counts -> 3
    Enum.count(counts, fn c -> c == 2 end) == 2 -> 2
    2 in counts -> 1
    true -> 0
  end
end

score = fn {hand, _bid} ->
  alph =
    String.split(hand, "", trim: true)
    |> Enum.map(fn letter -> Map.get(letter_map, letter, letter) end)
    |> Enum.join("")

  case hand do
    "JJJJJ" ->
      {classify.(hand), alph}

    _ ->
      {k, _v} =
        String.split(hand, "", trim: true)
        |> Enum.frequencies()
        |> Enum.filter(fn {k, _v} -> k != "J" end)
        |> Enum.max_by(fn {_k, v} -> v end)

      hand = if "J" in String.split(hand, ""), do: String.replace(hand, "J", k), else: hand

      {classify.(hand), alph}
  end
end

example
|> Kino.Input.read()
|> String.split(["\n", " "], trim: true)
|> Enum.chunk_every(2)
|> Enum.map(fn [card, bid | _] ->
  {card, String.to_integer(bid)}
end)
|> Enum.sort_by(fn hand_bid -> score.(hand_bid) end)
|> Enum.reduce({0, 1}, fn {_, bid}, {total, i} ->
  {total + i * bid, i + 1}
end)