深度优先广度优先

深度优先搜索

def depth_tree(tree_node)
  if tree_node is not None:
  print(tree_node.data)
  if tree_node._left is not None:
    return depth_tree(tree_node._left)
  if tree_node._right is not None:
    return depth_tree(tree_node._right)

广度优先搜索（队列实现）

def level_queue(root):
  if root is None:
    return
  node = root 
  my_queue = []
  my_queue.append(node)
  while my_queue:
    node = my_queue.pop(0)
    print(node.elem)
    if node.lchild is not None:
      my_queue.append(node.lchild)
    if node.rchild is not None:
      my_queue.append(node.rchild)