Day 10: Factory

Day 10: Factory

Day 10: Factory

Part 1

defmodule Awesome do
  def combination(_, 0), do: [[]]
  def combination([], _), do: []

  def combination([x | xs], n) do
    for(y <- combination(xs, n - 1), do: [x | y]) ++ combination(xs, n)
  end
end

defmodule AdventOfCode2025Day10Part1Solver do
  def run(list) do
    Enum.reduce(list, [], &amp;solve/2)
    |> Enum.sum()
  end

  defp solve({pattern, buttons}, acc) do
    Range.new(1, Enum.count(buttons))
    |> Enum.reduce_while(nil, fn i, nil ->
      Awesome.combination(buttons, i)
      |> Enum.any?(fn selected_buttons -> do_solve(selected_buttons, pattern) end)
      |> if(do: {:halt, i}, else: {:cont, nil})
    end)
    |> List.wrap()
    |> Kernel.++(acc)
  end

  defp do_solve(selected_buttons, pattern) do
    init = String.duplicate(".", String.length(pattern)) |> String.to_charlist()
    
    selected_buttons
    |> Enum.reduce(init, fn list, acc ->
      Enum.reduce(list, acc, fn i, acc ->
        List.update_at(acc, i, fn 
          ?. -> ?#
          ?# -> ?.
        end)
      end)
    end)
    |> List.to_string()
    |> Kernel.==(pattern)    
  end
end

defmodule AdventOfCode2025Day10Part1 do
  def run(input) do
    input
    |> parse_input()
    |> solve()
  end

  defp solve(list), do: AdventOfCode2025Day10Part1Solver.run(list)

  defp parse_input(input) do
    String.split(input, "\n", trim: true)
    |> Enum.map(&amp;parse_line/1)
  end

  defp parse_line(line) do
    line =
      case String.split(line, "{", parts: 2) do
        [left, _] -> left
        [left] -> left
      end

    [_, pattern] = Regex.run(~r/\[([.#]+)\]/, line)
    buttons =
      Regex.scan(~r/\(([^)]*)\)/, line)
      |> Enum.map(fn [_, inside] ->
        inside
        |> String.split(",", trim: true)
        |> Enum.map(&amp;String.to_integer/1)
      end)

    {pattern, buttons}
  end
end

input = """
[.##.] (3) (1,3) (2) (2,3) (0,2) (0,1) {3,5,4,7}
[...#.] (0,2,3,4) (2,3) (0,4) (0,1,2) (1,2,3,4) {7,5,12,7,2}
[.###.#] (0,1,2,3,4) (0,3,4) (0,1,2,4,5) (1,2) {10,11,11,5,10,5}
"""

AdventOfCode2025Day10Part1.run(input)