AoC 2023 D01

Mix.install([:kino])

defmodule Utils do
  def split(line, sep \\ "") do
    String.split(line, sep, trim: true)
  end

  def split_all_lines(text, sep \\ "") do
    text
    |> String.split("\n", trim: true)
    |> Enum.map(&split(&1, sep))
  end

  def to_numbers(number) when is_binary(number) do
    String.to_integer(number)
  end

  def to_numbers(numbers) when is_list(numbers) do
    Enum.map(numbers, &to_numbers/1)
  end

  def to_matrix(text, sep \\ "") do
    text
    |> split_all_lines(sep)
    |> then(fn data ->
      for {row, r} <- Enum.with_index(data), {col, c} <- Enum.with_index(row) do
        {{r, c}, col}
      end
    end)
    |> Map.new()
  end
end

Setup

import Utils

input = Kino.Input.textarea("Input:")

text = Kino.Input.read(input)

data = split(text, "\n")

P1

defmodule P1 do
  def solve(data) do
    for line <- data do
      Regex.scan(~r/\d/, line)
    end
    |> Enum.map(fn list ->
      [m] = List.first(list)
      [n] = List.last(list)
      (m <> n) |> String.to_integer()
    end)
    |> Enum.sum()
  end
end

# P1.solve(data)

P2

defmodule P2 do
  def solve(data) do
    for line <- data do
      Regex.scan(~r/\d|one|two|three|four|five|six|seven|eight|nine/, line)
    end
    |> Enum.map(fn list ->
      [m] = List.first(list)
      [n] = List.last(list)
      (to_num(m) <> to_num(n)) |> String.to_integer()
    end)
    |> Enum.sum()
  end

  defp to_num(n) do
    case n do
      "one" -> "1"
      "two" -> "2"
      "three" -> "3"
      "four" -> "4"
      "five" -> "5"
      "six" -> "6"
      "seven" -> "7"
      "eight" -> "8"
      "nine" -> "9"
      n -> n
    end
  end
end

P2.solve(data)