bst.rb

class BinaryTree
  def initialize(data = nil)
    @data = data
  end

  def left
    @left ||= BinaryTree.new
  end

  def right
    @right ||= BinaryTree.new
  end

  def insert(data)
    if @data.nil?
      @data = data
    elsif data < @data
      left.insert(data)
    else
      right.insert(data)
    end
  end

  def include?(data)
    if @data.nil?
      false
    elsif data == @data
      true
    elsif data < @data
      left.include? data
    else
      right.include? data
    end
  end

  def all
    if @data.nil?
      []
    else
      left.all + [@data] + right.all
    end
  end

  def count
    if @data.nil?
      0
    else
     1 + left.count + right.count
    end
  end


  # health(0)
  def health(desired_depth, current_depth = 0, total_count = count)
    if @data.nil?
      []
    elsif desired_depth == current_depth
      [[data, count, count.to_f / total_count]]
    else
      left.health(desired_depth, current_depth + 1, total_count) +
        right.health(desired_depth, current_depth + 1, total_count)
    end
  end
end

bt = BinaryTree.new
bt.insert(5)
puts bt.data

bt.insert(4)
bt.insert(7)
puts bt.left.data
puts bt.right.data

puts bt.include? 5
puts bt.include? 4
puts bt.include? 7
puts bt.include? 21

puts bt.all.inspect

puts bt.count
puts bt.health(0).inspect
puts bt.health(1).inspect

(1..10).to_a.shuffle.each do |i|
  bt.insert(i)
end

puts bt.health(2).inspect