python实现的二叉树算法和kmp算法实例

主要是：前序遍历、中序遍历、后序遍历、层级遍历、非递归前序遍历、非递归中序遍历、非递归后序遍历

代码如下:
#!/usr/bin/env python
#-*- coding:utf8 -*-

class TreeNode(object):
    def __init__(self, data=None, left=None, right=None):
        self.data = data
        self.left = left
        self.right = right

class Tree(object):
    def __init__(self, root=None):
        self.root = None

    def makeTree(self, data, left, right):
        self.root = TreeNode(data, left, right)

    def is_empty(self):
        """是否为空 """
        if self.root is None:
            return True
        return False

    def preOrder(self, r):
        """前序遍历 """
        if not r.is_empty():
            print r.root.data
            if r.root.left is not None:
                r.preOrder(r.root.left)
            if r.root.right is not None:
                r.preOrder(r.root.right)

    def inOrder(self, r):
        """中序遍历 """
        if not r.is_empty():
            if r.root.left is not None:
                r.preOrder(r.root.left)
            print r.root.data
            if r.root.right is not None:
                r.preOrder(r.root.right)

    def postOrder(self, r):
        """后续遍历 """
        if not r.is_empty():
            if r.root.left is not None:
                r.preOrder(r.root.left)
            print r.root.data
            if r.root.right is not None: