REVERSE A BINARY TREE

reverse_binary_tree.rb

Node = Struct.new(:left, :right)
Tree = Node.new(
  Node.new(
    Node.new(
      0,
      1
    ),
    Node.new(
      2,
      3
    )
  ),
  Node.new(
    Node.new(
      4,
      5
    ),
    Node.new(
      6,
      7
    )
  )
)

class ReverseBinaryTree
  def self.call(tree)
    new.call(tree)
  end

  def call(tree)
    swap_children(tree)
    traverse_depth_first(tree)
  end

  def traverse_depth_first(tree)
    tree.each do |node|
      if node.is_a?(Node)
        swap_children(node)
        traverse_depth_first(node)
      else
        puts node
      end
    end
  end

  def swap_children(node)
    tmp = node.left
    node.left = node.right
    node.right = tmp
  end
end

ReverseBinaryTree.new.call(Tree)