#實現(xiàn)樹結(jié)構(gòu)的類，樹的節(jié)點有三個私有屬性 左指針 右指針 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._right

if __name__ == '__main__':
  #實例化根節(jié)點
  root_node = Node('a')
  # root_node.set_data('a')
  #實例化左子節(jié)點
  left_node = Node('b')
  #實例化右子節(jié)點
  right_node = Node('c')
  
  #給根節(jié)點的左指針賦值，使其指向左子節(jié)點
  root_node.set_left(left_node)
  #給根節(jié)點的右指針賦值，使其指向右子節(jié)點
  root_node.set_right(right_node)

  print(root_node.get_data(),root_node.get_left().get_data(),root_node.get_right().get_data())

#實現(xiàn)樹結(jié)構(gòu)的類，樹的節(jié)點有三個私有屬性 左指針 右指針 自己的值
class Node():

  def __init__(self,data =None,left=None,right = None):
    self._data = data
    self._left = left
    self._right = right


#先序遍歷 遍歷過程 根左右
def pro_order(tree):
  if tree == None:
    return False
  print(tree._data)
  pro_order(tree._left)
  pro_order(tree._right)

#后序遍歷
def pos_order(tree):
  if tree == None:
    return False
  # print(tree.get_data())
  pos_order(tree._left)
  pos_order(tree._right)
  print(tree._data)

#中序遍歷
def mid_order(tree):
  if tree == None:
    return False
  # print(tree.get_data())
  mid_order(tree._left)
  print(tree._data)
  mid_order(tree._right)


#層次遍歷
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)