Python_二叉树

BinaryTree.py

 '''二叉树：是每个节点最多有两个子树（分别称为左子树和右子树）的树结构，二叉树的第i层最多有2**(i-1)个节点，常用于排序或查找'''
 class BinaryTree:
     def __init__(self,value):
         self.__left = None
         self.__right = None
         self.__data = value

     #析构函数
     def __del__(self):
         del self.__data

     #创建左子树
     def insertLeftChild(self,value):
         if self.__left:
             print('Left child tree already exists.')
         else:
             self.__left = BinaryTree(value)
             return self.__left

     #创建右子树
     def insertRightChild(self,value):
         if self.__right:
             print('Right child tree already exits.')
         else:
             self.__right = BinaryTree(value)
             return self.__right

     def show(self):
         print(self.__data)

     #前序遍历
     def preOrder(self):
         print(self.__data)  #输出根节点的值
         if self.__left:
             self.__left.preOrder()  #遍历左子树
         if self.__right:
             self.__right.preOrder() #遍历右子树

     def postOrder(self):
         if self.__left:
             self.__left.postOrder()
         if self.__right:
             self.__right.postOrder()
         print(self.__data)

     def inOrder(self):  #中序遍历
         if self.__left:
             self.__left.inOrder()
         print(self.__data)
         if self.__right:
             self.__right.inOrder()

 if __name__ == '__main__':
     print('Please use me a module')

useBinaryTree.py

 from BinaryTree import BinaryTree
 root = BinaryTree('root')
 b=root.insertRightChild('B')
 a=root.insertLeftChild('A')
 c=a.insertLeftChild('C')
 d=c.insertRightChild('D')
 e=b.insertRightChild('E')
 f=e.insertLeftChild('F')
 root.inOrder()
 # C
 # D
 # A
 # root
 # B
 # F
 # E
 root.postOrder()
 # D
 # C
 # A
 # F
 # E
 # B
 # root
 b.inOrder()
 # B
 # F
 # E