python3实现二叉树的遍历与递归算法解析(小结)

#实现树结构的类，树的节点有三个私有属性 左指针 右指针 自身的值class Node():  def __init__(self,data=None):    self._data = data    self._left = None    self._right = None  def set_data(self,data):    self._data = data  def get_data(self):    return self._data  def set_left(self,node):    self._left = node  def get_left(self):    return self._left  def set_right(self,node):    self._right = node  def get_right(self):    return self._rightif __name__ == '__main__':  #实例化根节点  root_node = Node('a')  # root_node.set_data('a')  #实例化左子节点  left_node = Node('b')  #实例化右子节点  right_node = Node('c')    #给根节点的左指针赋值，使其指向左子节点  root_node.set_left(left_node)  #给根节点的右指针赋值，使其指向右子节点  root_node.set_right(right_node)  print(root_node.get_data(),root_node.get_left().get_data(),root_node.get_right().get_data())

#实现树结构的类，树的节点有三个私有属性 左指针 右指针 自己的值class Node():  def __init__(self,data =None,left=None,right = None):    self._data = data    self._left = left    self._right = right#先序遍历 遍历过程 根左右def pro_order(tree):  if tree == None:    return False  print(tree._data)  pro_order(tree._left)  pro_order(tree._right)#后序遍历def pos_order(tree):  if tree == None:    return False  # print(tree.get_data())  pos_order(tree._left)  pos_order(tree._right)  print(tree._data)#中序遍历def mid_order(tree):  if tree == None:    return False  # print(tree.get_data())  mid_order(tree._left)  print(tree._data)  mid_order(tree._right)#层次遍历def row_order(tree):  # print(tree._data)  queue = []  queue.append(tree)  while True:    if queue==[]:      break    print(queue[0]._data)    first_tree = queue[0]    if first_tree._left != None:      queue.append(first_tree._left)    if first_tree._right != None:      queue.append(first_tree._right)    queue.remove(first_tree)if __name__ == '__main__':  tree = Node('A',Node('B',Node('D'),Node('E')),Node('C',Node('F'),Node('G')))  pro_order(tree)  mid_order(tree)  pos_order(tree)