【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 "\n","-"*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 "\n","-"*5," Preorder  ","-"*5
     tree.preorder(tree.root)
     print "\n\n","-"*5,"  Inorder  ","-"*5
     tree.inorder(tree.root)
     print "\n\n","-"*5," Postorder ","-"*5
     tree.postorder(tree.root)
     print "\n\n","-"*5," Lvlorder  ","-"*5
     tree.levelorder()
     print "\n\n"