umarsheikh

# method: flatten_array
# arguments: an unflattened array, and output array, initially set to [].
# output: a flattened array, so that arbitrary nesting of arrays is removed.
# the method employs tail recursion. It loops over each element of the array.
# if the current element is not an array, it adds it to the array it is building for output.
# but if the current element is an array, then it will call itself recursively so that the next call can iterate over this array element and add items from it recursively.


def flatten_array(array, start=[])
  array.each do |elem|

umarsheikh

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

def traverse(node, k, depth=0)
  return if k < 0