advent-of-code/2023/day11.rb

42 lines
905 B
Ruby

input = ARGF.read.strip
by_row = input.lines.map(&:rstrip).map { |line| line.split("") }
def needs_expand(data)
expand = []
data.each_with_index { |row, i| expand << i if row.all? { |c| c == "." } }
expand
end
def print_cosmos(cosmos)
cosmos.each do |line|
puts line.join("")
end
end
# do expansion
row_expand = needs_expand(by_row)
row_expand.reverse.each do |i|
by_row.insert(i, by_row[i].dup)
end
by_column = by_row.transpose
col_expand = needs_expand(by_column)
col_expand.reverse.each do |i|
by_column.insert(i, by_column[i].dup)
end
cosmos = by_column.transpose
# find galaxies
galaxies = []
(0...cosmos.first.length).each do |x|
(0...cosmos.length).each do |y|
galaxies << [x, y] if cosmos[y][x] == "#"
end
end
def galaxy_distance(a, b)
(a[0] - b[0]).abs + (a[1] - b[1]).abs
end
puts "Part 1: #{galaxies.combination(2).map { |a, b| galaxy_distance(a, b) }.sum}"