13 Red-black Trees 

Red-black trees are one of many search-tree schemes that are "balanced" in order to guarantee that basic dynamic-set operations take O(lgn) time in the worst case.

Red-black trees 是许多搜索树框架中得一个。这些树为了保证基本的动态集合在最坏情况下操作时间在0(lgn ),采取了自平衡。

 

 

A red-black tree is a binary tree that satisfies the following red-black properties:

1. Every node is either red or black. 

2. The root is black. 

3. Every leaf (NIL) is black. 

4. If a node is red, then both its children are black. 

5. For each node, all simple paths from the node to descendant leaves contain the same number of black nodes. 

1 所有的节点非红即黑

2 根是黑的

3 叶子(Nil)也是黑得

4 一个节点是红得,孩子必定是黑的。

5 对于每个节点,从这个节点到叶子的任意路径包含同样数量的黑的。

 

red-black tree 的属性从2-5感觉都是针对黑色的限制。

 

an example of a red-black tree.

 

As a matter of convenience in dealing with boundary conditions in red-black

tree code, we use a single sentinel to represent NIL

All pointers to NIL are replaced by pointers to the sentinel T.nil

所有指向空的都被替换成指向哨兵 T.nil 了

 

 

In the remainder of this chapter, we omit the leaves when we draw red-black trees, as shown

 

We call the number of black nodes on any simple path from, but not including, a node x down to a leaf the black-height of the node, denoted bh(x) 

 

13.2 Rotations 

We change the pointer structure through rotation, which is a local operation in a search tree that preserves the binary-search-tree property.

我们通过rotation来改变指针结构。它是保留搜索树属性的一个本地操作。

 

 

13.3 Insertion 

We can insert a node into an n-node red-black tree in O(lgn) time.

To do so, we use a slightly modified version of the TREE-INSERT procedure (Section 12.3) to insert node ́ into the tree T as if it were an ordinary binary search tree, and then we color z red.

 

 

 

Case1:

 

Case 2 and case 3

 

 

13.4 Deletion 

Like the other basic operations on an n-node red-black tree, deletion of a node takes time O(lgn ). Deleting a node from a red-black tree  is a bit more complicated than inserting a node . 

First ,we need to customize the TRANSPLANT subroutine  that Tree-Delete calls so that it applies to a red-black tree :

 

 

 

 

 

 

 

Here is the red-black delete tree program  :

 

 

Finally, if node y was black, we might have introduced one or more violations of the red-black properties, and so we call RB-DELETE-FIXUP in line 22 to restore the red-black properties. If y was red, the red-black properties still hold when y is removed or moved, for the following reasons:

如果节点y是黑色的,我们可能引入一个或多个违反红黑树性质。如果y是红色的,则红黑树的性质能得到保证。原因如下:

1. No black-heights in the tree have changed. 

黑色深度没有变化

2. No red nodes have been made adjacent. Because y takes z's place in the tree, along with z's color, we cannot have two adjacent red nodes at y's new position in the tree. In addition, if y was not ́'s right child, then y's original right child x replaces y in the tree. If y is red, then x must be black, and so replacing y by x cannot cause two red nodes to become adjacent. 

没有红色节点相邻。因为y取代了z得位置,并且取得了z得颜色,z原来是具有红黑树属性的,所以替换了以后仍然有。

另外,如果y不是z的右孩子,则y的原来位置被x取代了。如果y是红色的话,那么x肯定是黑色的,所以被x取代y 不可能导致两个红色节点相邻。

 

3. Since y could not have been the root if it was red, the root remains black. 

如果y是红色的话,y肯定不是根,因此根仍然保持黑色。

 

 

If node y was black, three problems may arise, which the call of RB-DELETE- FIXUP will remedy. 

First, if y had been the root and a red child of y becomes the new root, we have violated property 2. 

首先如果y是根,并且y的一个红孩子成为了新根,那么违反 根是黑色的 属性。

 

Second, if both x and x.p are red, then we have violated property 4. 

如果x和x.p 是红色的,那么我们可能违反 红色节点不能相邻这一条。

 

Third, moving y within the tree causes any simple path that previously contained y to have one fewer black node. Thus, property 5 is now violated by any ancestor of y in the tree. 

第三,如果移动y,那么任意一条原先包含y的路线可能比其他的路线少一条黑色,因此,从任意一节点到叶子的黑色节点数是相同的。

 

We can correct the violation of property 5 by saying that node x, now occupying y's original position, has an "extra" black. 

我们可以纠正 第五条属性 通过将现在占据y的原来位置的x的属性 有一个额外的黑色。

 

That is, if we add 1 to the count of black nodes on any simple path that contains x, then under this interpretation, property 5 holds. 

也就是说,在我们计算从任意一条包括x节点的简单路径的时候,多增加1就能保持 属性5 。

When we remove or move the black node y, we "push" its blackness onto node x.

当我们移动黑色节点y时,我们将她的黑色推到节点x上。

 

 The problem is that now node x is neither red nor black, thereby violating property 1. 

现在问题是现在的节点x既不是黑色也不是红色,违反了属性1.

 

Instead,node x is either "doubly black" or "red-and-black," and it contributes either 2 or 1, respectively, to the count of black nodes on simple paths containing x.

节点x是双黑,或红黑,在计算包含x的简单路径上它将分别贡献一个或两个。

 The color attribute of x will still be either RED (if x is red-and-black) or BLACK (if x is doubly black). 

x的属相将仍然是红色(如果x是红黑)或黑色(如果x是双黑)。

In other words, the extra black on a node is reflected in x's pointing to the node rather than in the color attribute.

换句话说,一个节点的额外的黑色反应了x得位置而非颜色属性。

 

 

Case1: x'sibling w is red 

通过转化,转换成Case2,3,4 的任意一种

Case2 :x's sibling w is black ,and both of w's children are black 

即x的兄弟,还有兄弟的孩子都是黑色,则让x的兄弟便红,x转移到x得父节点

Case3:x的兄弟是黑色,兄弟的右孩子是红色。则通过转换,转换成Case4

Case4:x的兄弟是黑色,兄弟的左孩子是红色。这个就可以解决黑色节点的问题。

 

 

 

 

13 Red-black Trees的更多相关文章

  1. Red–black tree ---reference wiki

    source address:http://en.wikipedia.org/wiki/Red%E2%80%93black_tree A red–black tree is a type of sel ...

  2. 【wiki】红帽linux

    Red Hat Enterprise Linux From Wikipedia, the free encyclopedia wiki 上面红帽的版本信息. https://en.wikipedia. ...

  3. 深入探索RB-tree数据结构

    引子 部门在各个团队推广软件通用技能矩阵工具,希望通过度量找到能力薄弱点,引导团队进行改进.从我们团队的数据上看,团队在数据结构和算法上的短板明显,需要加强,这也是写这篇文章的背后的初衷. 数据结构和 ...

  4. OCJP(1Z0-851) 模拟题分析(五)over

    Exam : 1Z0-851 Java Standard Edition 6 Programmer Certified Professional Exam 以下分析全都是我自己分析或者参考网上的,定有 ...

  5. 2015GitWebRTC编译实录16

    新问题,看应该是视频编解码那里出问题了.找找看.WebRtc VoiceEngine codecs:ISAC/16000/1 (103)ISAC/32000/1 (104)Unexpected cod ...

  6. 转:Hide data inside pointers(在指针中隐藏数据)

    该文介绍了如何使用指针中一些未使用的位来隐藏一些数据. When we write C code, pointers are everywhere. We can make a little extr ...

  7. 红黑树(三)之 Linux内核中红黑树的经典实现

    概要 前面分别介绍了红黑树的理论知识 以及 通过C语言实现了红黑树.本章继续会红黑树进行介绍,下面将Linux 内核中的红黑树单独移植出来进行测试验证.若读者对红黑树的理论知识不熟悉,建立先学习红黑树 ...

  8. 【转】const和static readonly

    我们都知道,const和static readonly的确很像:通过类名而不是对象名进行访问,在程序中只读等等.在多数情况下可以混用.二者本质的区别在于,const的值是在编译期间确定的,因此只能在声 ...

  9. (C#) What is the difference between "const" and "static readonly" ?

    const int a must be initialized initialization must be at compile time readonly int a can use defaul ...

  10. linux内核-红黑树

    //rbtree.h /*   Red Black Trees   (C) 1999  Andrea Arcangeli <andrea@suse.de>     This program ...

随机推荐

  1. 设计模式-(9)中介者模式(swift)

    在对象去耦合的模式中,有两种模式:中介者模式,观察者模式 一,概念 用一个中介对象来封装一系列的对象交互.中介者使各对象不需要显式地相互引用,从而使其耦合松散,而且可以独立地改变它们之间的交互. 这个 ...

  2. winform 无法修改控件的location

    dock and location 是因为设置了控件的Dock,导致无法修改

  3. 如何完成DEDE CMS外部数据库调用|不同数据库调用数据

    dedecms如何完成2个数据库内容彼此调用?这是笔者今日要和我们共享的内容.百度了一大堆,大多语焉不详.常识有限,所以就说下笔者的做法, 能够还有其他有用的办法,欢送共享.笔者站点是dedecms5 ...

  4. HTML5、javascript写的craps游戏

    1. [代码][HTML]代码   <!DOCTYPE HTML><html><head><meta charset="utf-8"> ...

  5. Windows代码heap内存分析实战

    知识这东西有时候很奇怪,每次当你重新审视他的时候可能都会有新的收获.最近为了研究一个内存相关的问题,把windows heap相关的内容又复习了一遍,收获不小,记录一下,希望有朋友使用的时候少走些弯路 ...

  6. RobotFrameWork--selenium2模拟chrome的user agent

    ${options}= Evaluate sys.modules['selenium.webdriver'].ChromeOptions() sys, selenium.webdriver ${opt ...

  7. asp.net Identity2 角色(Role)的使用(二)角色管理,角色控制器和视图

    新建一个AdminViewModel 文件,建立视图模型类 public class RoleViewModel { public string Id { get; set; } [Required( ...

  8. 本地测试出现:Call to undefined function curl_init()

    网上搜索Call to undefined function curl_init(),清一色的以下解决办法: 1.在php.ini中找到extension=php_curl.dll,去掉前面的,php ...

  9. Ubuntu 12.04的gnome classic panel添加程序快捷键(转载)

    How to add applets to the Gnome classic panel in Ubuntu 12.04 转自:http://www.borfast.com/blog/how-add ...

  10. RTSP协议简介(转载)

    转自:http://ilinux.iteye.com/blog/505753 Real Time Streaming Protocol 或 者RTSP(实时流媒体协议),是由Real network ...