Level-order traversal of a binary tree

level_order_traversal.rb

class Node
  attr_accessor :value, :left, :right
  def initialize(value)
    @value = value
  end
end

def level_order_traversal(node)
  queue = [node]
  
  loop do
    nxt = queue.shift
    puts nxt.value
    
    queue.push nxt.left if nxt.left
    queue.push nxt.right if nxt.right
    
    break if queue.empty?
  end
end

a = Node.new(1)
a.left = Node.new(2)
a.left.left = Node.new(3)
a.left.right = Node.new(4)
a.right = Node.new(5)

level_order_traversal(a) # 1, 2, 5, 3, 4