#!/usr/bin/env python3.3
# -*- coding:utf-8 -*-
# Copyright 2013
'''
对任何节点X
1）其左子树中的关键字最大不大于key[X]
2）其右子树中的关键字最小不小于key[X]
'''
class Node:
def __init__(self, key):
self.key = key
self.left = None
self.right = None
self.parent = None
def __str__(self):
return str(self.key)
def successor(self):
if self.right is not None:
successor = self.right
while successor.left is not None:
successor = successor.left
return successor
else:
x = self
successor = x.parent
while successor is not None and successor.left == x:
x = successor
successor = successor.parent
return successor
class BSTree:
def __init__(self):
self.root = None
def insert(self, key):
node = Node(key)
if self.root is None:
self.root = node
else:
root = self.root
while root is not None:
if key < root.key:
if root.left is not None:
root = root.left
else:
root.left = node
node.parent = root
break
else:
if root.right is not None:
root = root.right
else:
root.right = node
node.parent = root
break
def delete(self, key):
node = self.search(key)
if node is not None:
if node.left is not None and node.right is not None:
# 把要删除的节点替换为其后继节点
successor = node.right
while successor.left is not None:
successor = successor.left
node.data = successor.data
node = successor
if node.left is not None:
# 要删除的节点没有右儿子
node.left.parent = node.parent
if node.parent is not None:
if node.parent.left == node:
node.parent.left = node.left
else:
node.parent.right = node.left
else:
self.root = node.left
elif node.right is not None:
# 要删除的节点没有左儿子
node.right.parent = node.parent
if node.parent is not None:
if node.parent.left == node:
node.parent.left = node.right
else:
node.parent.right = node.right
else:
self.root = node.right
else:
# 要删除的节点为叶子节点
if node.parent is not None:
if node.parent.left == node:
node.parent.left = None
else:
node.parent.right = None
else:
self.root = None
def serach(self, key):
node = self.root
while node is not None:
if key == node.key:
return node
elif key < node.key :
node = node.left
else:
node = node.right
def minimum(self):
node = self.root
while node.left is not None:
node = node.left
return node
def maximum(self):
node = self.root
while node.right is not None:
node = node.right
return node
def nodes(self):
if self.root is not None:
node_list = [self.root]
while len(node_list) > 0:
node = node_list.pop(0)
yield node
if node.left is not None:
node_list.append(node.left)
if node.right is not None:
node_list.append(node.right)
def check_bstree(bst):
if bst.root is not None:
node_list = [bst.root]
while len(node_list) > 0:
node = node_list.pop(0)
if node.left is not None:
if node.key < node.left.key:
print('sort_error')
break
node_list.append(node.left)
if node.right is not None:
if node.key > node.right.key:
print('sort_error')
break
node_list.append(node.right)
print('ok')
else:
print('empty')
