python数据结构之二叉树的建立实例

先建立二叉树节点，有一个data数据域，left，right 两个指针域

# -*- 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 BTree(object):    def __init__(self, root=0):
        self.root = root

手动建立二叉树

node1 = TreeNode(data=1)
node2 = TreeNode(node1, 0, 2)
node3 = TreeNode(data=3)
node4 = TreeNode(data=4)
node5 = TreeNode(node3, node4, 5)
node6 = TreeNode(node2, node5, 6)
node7 = TreeNode(node6, 0, 7)
node8 = TreeNode(data=8)
root = TreeNode(node7, node8, 'root')
bt = BTree(root)

然后会生成下面的二叉树

# 生成的二叉树# ------------------------
#          root
#       7        8
#     6
#   2   5
# 1    3 4
#
# -------------------------

除了 手动一个个的制定 node 节点，还可以创建一个 create 方法，接受用户输入添加二叉树节点。。。使用前续方式添加 ，代码如下：

# -*- 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 BTree(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()
        treenode.right = self.create()

使用create创建二叉树

#运行文件 在交互解释器下面运行bt = BTree()
bt.create()
enter a value:9
enter a value:7
enter a value:6
enter a value:2
enter a value:1
enter a value:'#'
enter a value:'#'
enter a value:'#'
enter a value:5
enter a value:3
enter a value:'#'
enter a value:'#'
enter a value:4
enter a value:'#'
enter a value:'#'
enter a value:'#'
enter a value:8
enter a value:'#'
enter a value:'#'

通过 create 也可以得到同样的效果