v2ex-694808.rb

class Node
  attr_accessor :parent, :value, :width
  attr_reader :left, :right
  def initialize(value, left=nil, right=nil)
    @value = value
    @parent = nil
    self.left = left
    self.right = right
  end

  def left=node
    @left = node
    node&.parent = self
  end

  def right=node
    @right = node
    node&.parent = self
  end

  def my_width
    value.to_s.size
  end

  def left_width
    @left&.width || (my_width / 2)
  end

  def right_width
    @right&.width || (my_width / 2)
  end

  def width
    left_width + right_width + 1
  end

  def draw_me
    value.to_s.rjust(left_width + my_width / 2 + 1).ljust(width)
  end

  def draw_sticks
    return nil unless @left || @right
    left_stick = (@left ? '/' : '').rjust(left_width)
    right_stick = (@right ? '\\' : '').ljust(right_width)
    left_stick + ' ' + right_stick
  end

  def draw
    pic = [draw_me]
    sticks = draw_sticks
    return pic unless sticks

    pic << sticks

    left_pic = @left&.draw || []
    right_pic = @right&.draw || []

    depth = [left_pic.size, right_pic.size].max
    left_pic.fill(' ' * left_width, left_pic.size...depth)
    right_pic.fill(' ' * right_width, right_pic.size...depth)
    pic += left_pic.zip(right_pic).map {|l,r| l + ' ' + r}

    pic
  end
end

l = Node.new 20
l = Node.new 16, l
r = Node.new 776655
r = Node.new 13, r
l1 = Node.new 7, l, r
l = Node.new 17
r = Node.new 24
r1 = Node.new 5, l, r
root = Node.new 3, l1, r1

puts root.draw

#                3
#               / \
#      7             5
#     / \           / \
#    16        13  17  24
#   /         /
#  20    776655

l = Node.new 100
r = Node.new 50
10.times do |i|
  l = Node.new i, l
  r = Node.new i, nil, r
end
root = Node.new 123, l, r
puts root.draw

#             123
#             / \
#             9 9
#            /   \
#            8   8
#           /     \
#           7     7
#          /       \
#          6       6
#         /         \
#         5         5
#        /           \
#        4           4
#       /             \
#       3             3
#      /               \
#      2               2
#     /                 \
#     1                 1
#    /                   \
#    0                   0
#   /                     \
# 100                      50