本来打算一个学期分别用C++、Python、Java实现数据结构，看来要提前了

这个是Python版本，我写的数据结构尽量保持灵活性，本文bt1是一般的插入法建立二叉树结构，bt2就是可以任意输入，至于树的高度的递归和非递归实现等等，在C++里实现过就不再重复。

#Date     : 2013-9-12#Author   : DVD0423#Function : 二叉树class Node:    def __init__(self, value = None, left = None, right = None):        self.value = value        self.left = left        self.right = right    def visit(self):        print(self.value)        class BTree:    def __init__(self, root = Node()):        self.root = root    def CreateBTree(self, _list = []):        #层序遍历，产生二叉树结构        length = len(_list)        node = []          for i in range(length):            node.append(Node())            node[i].value = _list[i]                       front = 0        rear = 0        while(rear != length):            rear = rear + 1            if rear >= length:                break            node[front].left = node[rear]            rear = rear + 1            if rear >= length:                break            node[front].right = node[rear]            front = front + 1        #下面这句没有必要，因为初始化就是None,但是逻辑上要有        while(front != length):            node[front].left = None            node[front].right = None            front = front + 1            self.root = node[0]            def Traverse(self, method):        def PostOrder(node):                        if node:                PostOrder(node.left)                PostOrder(node.right)                node.visit()        def InOrder(node):            if node:                InOrder(node.left)                node.visit()                InOrder(node.right)        def PreOrder(node):            if node:                node.visit()                PreOrder(node.left)                PreOrder(node.right)        def NoRecTraverse(node):            ls = []            while True:                if node:                    ls.append(node)                    node.visit()                    node = node.left                else:                    if len(ls) != 0:                        node = ls.pop()                    node = node.right                    if len(ls) == 0 and node == None:                        break                            if method is 1:            print("后序遍历")            PostOrder(self.root)        elif method is 2:            print("中序遍历")            InOrder(self.root)        elif method is 3:            print("前序遍历")            PreOrder(self.root)        else:            print("非递归先序遍历")            NoRecTraverse(self.root)def InputInt():    seq = []      while True:          ch = input()          if ch is 'e':              break          seq.append(int(ch))    return seq        if __name__ == '__main__':    #两种方式建立二叉树    print("二叉树1：")    node3 = Node(3)    node2 = Node(2)    node1 = Node(1, node2, node3)    bt1 = BTree(node1)    bt1.Traverse(4)    print("二叉树2：")    ls = InputInt()     bt2 = BTree()    bt2.CreateBTree(ls)    bt2.Traverse(4)