11

🎄 Day 11

In Elixir

Another fun day with a problem that wasnt hard. Again had to think when implementing it using a functional language, but it went fine. I did my first recursive function with pattern matching experiment (i took the tail call optimized sum_list implementation from google, so that wasnt my first function with pattern matching :D). The code before i tried the pattern matching was this:

defp get_galaxies_in_row(row, x, y, result) do
	if x < length(row) do
		if row |> Enum.at(x) == "#" do
			row |> get_galaxies_in_row(x + 1, y, result ++ [{x, y}])
		else
			row |> get_galaxies_in_row(x + 1, y, result)
		end
	else
		result
	end
end

and after i applied pattern matching:

defp get_galaxies_in_row(_row, _x, _y, nil, result), do: result

defp get_galaxies_in_row(row, x, y, "#", result), do:
	row |> get_galaxies_in_row(x + 1, y, row |> Enum.at(x + 1), result ++ [{x, y}])

defp get_galaxies_in_row(row, x, y, _, result), do:
	row |> get_galaxies_in_row(x + 1, y, row |> Enum.at(x + 1), result)

Though it isnt the most beautiful, it did the job. As with Rust, after 3 days with Elixir im gonna switch langs. Tho i liked Elixir so much that i might return to it in the later days.

Quickstart

To run part 1 or part 2, do:

$ make part1
$ make part2