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