return self.__get_branch_node(self.root)
def __get_branch_node(self, root):
if root is 0:
return 0
if root.left is 0 and root.right is 0:
return 0
else:
return 1 + self.__get_branch_node(root.left) + self.__get_branch_node(root.right)
四、二叉树左右树互换
def replacelem(self):
''' 二叉树所有结点的左右子树相互交换 '''
self.__replace_element(self.root)
def __replace_element(self, root):
if root is 0:
return
root.left, root.right = root.right, root.left
self.__replace_element(root.left)
self.__replace_element(root.right)
这些方法和操作，都是运用递归。其实二叉树的定义也是一种递归。附上最后的完整代码：
# -*- coding: utf - 8 - *-
class TreeNode(object):
def __init__(self, left=0, right=0, data=0):
self.left = left
self.right = right
self.data = data
class BinaryTree(object):
def __init__(self, root=0):
self.root = root
def is_empty(self):
if self.root is 0:
return True
else:
return False
def create(self):
temp = input('enter a value:')
if temp is '#':
return 0
treenode = TreeNode(data=temp)
if self.root is 0:
self.root = treenode
treenode.left = self.create()
