Advent of Code #11 (in Crystal)

#crystal #adventofcode

I've been trying to add some meaningful commentary or thoughts along with each of these posts about Crystal, the puzzle, my solution, or coding in general. But today, I've got nothing. The puzzle wasn't all that complicated, and my code isn't all that great.

I gave up after day 11 last year, so hopefully I'll be able to get a little further this year!

Here's my code:

input = File.read("input").strip

lines = input.split("\n")

galaxies = lines.map_with_index do |line, row|
  line.scan(/#/).map { |match| {row, match.begin} }
end.flatten

empty_rows = (0..(lines.size - 1)).select do |row|
  !galaxies.find { |(x, _)| x == row }
end

empty_cols = (0..(lines[0].size - 1)).select do |col|
  !galaxies.find { |(_, y)| y == col }
end

expanded_universe = galaxies.map do |x, y|
  {
    x + empty_rows.select { |row| row < x }.size,
    y + empty_cols.select { |col| col < y }.size
  }
end

part1 = begin
  lengths = 0
  expanded_universe.each_cartesian(expanded_universe) do |(x1, y1), (x2, y2)|
    if {x1, y1} < {x2, y2}
      lengths += (x2 - x1).abs + (y2 - y1).abs
    end
  end
  lengths
end

puts part1

older_universe = galaxies.map do |x, y|
  {
    x.to_i64 + (empty_rows.select { |row| row < x }.size.to_i64 * 999_999_i64),
    y.to_i64 + (empty_cols.select { |col| col < y }.size.to_i64 * 999_999_i64)
  }
end

part2 = begin
  lengths = 0_i64
  older_universe.each_cartesian(older_universe) do |(x1, y1), (x2, y2)|
    if {x1, y1} < {x2, y2}
      lengths += (x2 - x1).abs + (y2 - y1).abs
    end
  end
  lengths
end

puts part2