Breadth First Search

bfs.py

"""
Let's assume we have a Binary Tree.

class BinaryTree(object):
  def __init__(self, val):
    self.val = val
    self.right = None
    self.left = None
    
I understand there may be some breaking of data encapsulation below.
This gist is for demonstration purposes.
"""

def enqueue_valid(node: BinaryTree, queue: list):
  for n in [node.left, node.right]:
    if n != None:
      queue.insert(0, n)
      
def bfs(root: BinaryTree):
  queue = [root]
  while len(queue) > 0:
    current_node = queue.pop()
    print(current_node.val)
    enqueue_valid(current_node, queue)