orbits = File.read("day6.txt").lines.map(&.chomp)
indirect = {} of String => Set(String)
direct = {} of String => Set(String)
edges_from = {} of String => Set(String)
orbits.each do |orbit|
  big, small = orbit.split(")")
  direct[big] ||= Set(String).new
  direct[big] << small
  (edges_from[big] ||= Set(String).new) << small
  (edges_from[small] ||= Set(String).new) << big
end

def compute_indirect(direct, indirect, for, current)
  indirect[for] ||= Set(String).new
  indirect[for] << current unless current == for
  return unless direct.has_key? current
  direct[current].each do |n|
    compute_indirect(direct, indirect, for, n)
  end
end

direct.each_key do |k|
  compute_indirect(direct, indirect, k, k)
end

total_direct = direct.values.map(&.size).sum
total_indirect = indirect.values.map(&.size).sum
puts total_indirect

start = "YOU"
dest = "SAN"
visited = Set(String).new
distances = { start => 0 }
queue = Set { start }
length = 0
loop do
  next_node = queue.min_by { |e| distances.fetch(e, 1000000) }
  queue.delete next_node

  break if next_node == dest
  next if visited.includes? next_node
  visited << next_node

  edges_from[next_node].each do |neighbor|
    distances[neighbor] ||= distances[next_node] + 1
    queue << neighbor
  end
end
puts distances[dest]-2