【DataStructure In Python】Python模拟二叉树

使用Python模拟二叉树的基本操作，感觉写起来很别扭。最近做编译的优化，觉得拓扑排序这种东西比较强多。近期刷ACM，发现STL不会用实在太伤了。决定花点儿时间学习一下STL。Boost其实也很强大。关于Python最近没什么时间搞了，忙着复试了。不过，挺喜欢这语言的。复试完继续大战PythonChallenge。

#! /usr/bin/env python
# DataStrucure Tree

import sys

class BTNode:
    
    def __init__(self, data, lchild=None, rchild=None):
        self.data = data
        self.lchild = lchild
        self.rchild = rchild

    def __str__(self):
        print "root: %s  lchild: %s  rchild: %s" % (data, lchild.data, rchild.data)
    

class BTree:
    
    def __init__(self, data=None, ldata=None, rdata=None):
        self.root = BTNode(data)
        self.root.lchild = BTNode(ldata)
        self.root.rchild = BTNode(rdata)
    
    def isEmpty(self):
        if self.root.data is None:
            return 1
        else:
            return 0
        

    def findNode(self, data):
        lst = []
        if self.isEmpty():
            print "The tree is empty."
            return None
        lst.append(self.root)
        while len(lst):
            BTemp = lst.pop(0)
            if BTemp.data == data:
                return BTemp
            if BTemp.lchild is not None:
                lst.append(BTemp.lchild)
            if BTemp.rchild is not None:
                lst.append(BTemp.rchild)
        return None
    
    def addchilds(self, data, ldata=None, rdata=None):
        BTemp = self.findNode(data)
        if BTemp is None:
            print "Can't find Node: %s"    % data
            return 0
        else:
            BTemp.lchild = None if ldata is None else BTNode(ldata)
            BTemp.rchild = None if rdata is None else BTNode(rdata)
            return 1

    def levelorder(self):
        if self.isEmpty():
            print "Root is not initialized."
            return
        lst = []
        lst.append(self.root)
        while len(lst):
            BTemp = lst.pop(0)
            print "-> %s" % BTemp.data,
            if BTemp.lchild is not None:
                lst.append(BTemp.lchild)
            if BTemp.rchild is not None:
                lst.append(BTemp.rchild)

    def preorder(self, Node):
        if Node is not None:
            print "-> %s" % Node.data,
            self.preorder(Node.lchild)
            self.preorder(Node.rchild)

    def inorder(self, Node):
        if Node is not None:
            self.inorder(Node.lchild)
            print "-> %s" % Node.data,
            self.inorder(Node.rchild)

    def postorder(self, Node):
        if Node is not None:
            self.postorder(Node.lchild)
            self.postorder(Node.rchild)
            print "-> %s" % Node.data,
    
    def __str__(self):
        if self.isEmpty():
            print "Root is not initialized."
            return None        
        tmp = ""
        lst = []
        lst.append(self.root)
        while len(lst):
            BTemp = lst.pop(0)
            tmp += ("-> %s " % BTemp.data)
            if BTemp.lchild is not None:
                lst.append(BTemp.lchild)
            if BTemp.rchild is not None:
                lst.append(BTemp.rchild)
        return tmp

if __name__ == "__main__":
    tree = BTree('A')
    tree.addchilds('A','B','C')
    tree.addchilds('B','D','E')
    tree.addchilds('C','F', None)
    print "
","-"*5,"    Find   ","-"*5
    tmp = tree.findNode('B')
    if tmp is not None:
        print "Found 'B', lchild is %s, rchild is %s." % (tmp.lchild.data, tmp.rchild.data)
    else:
        print "Not found 'B'."
    print "
","-"*5," Preorder  ","-"*5
    tree.preorder(tree.root)
    print "

","-"*5,"  Inorder  ","-"*5
    tree.inorder(tree.root)
    print "

","-"*5," Postorder ","-"*5
    tree.postorder(tree.root)
    print "

","-"*5," Lvlorder  ","-"*5
    tree.levelorder()
    print "

"