手写红黑树【数据结构】

前言

2024-3-30 10:52:57

昨天晚上B站看到的视频
00:00~01:00

以下内容源自《【数据结构】》
仅供学习交流使用

版权

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本文首次发布于CSDN平台
作者是CSDN@日星月云
博客主页是https://jsss-1.blog.csdn.net
禁止其他平台发布时删除以上此话

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我红黑树那么牛，你们凭什么不用我？

手写红黑树

一、理论知识

红黑树的特征

红黑树是一种二叉平衡树，只不过这个平衡不是那么严苛，只需黑平衡就行

1. 结点分为两种颜色
2. 根节点是黑色
3. 叶子结点是黑色的，叶子结点是不存储数据的空结点
4. 两个红结点不能相连，即红父亲的孩子都是黑色的
5. 对于任意一个结点，其到叶子结点的路径上的黑色结点数量是一致的

增加

视频

插入结点的颜色是红色的
因为是黑平衡，所以插入红结点有概率不会破坏这个规则

1. 父为黑，直接插入
2. 父叔为红，颜色调换
3. 父红叔黑，颜色调换，再移动
4. 父子不同向，先掰直，再执行第3种情况

删除

视频

https://www.processon.com/view/link/6550422f54fca5688e143664

二、手写代码

为了实现简单，加入parent的指针，和isLeaf的标记

可以使用HashMap用来记录每一个叶子结点的父亲结点，即键是叶子，值是父亲；
也可以直接在Node结点中加入双亲指针。
根节点的父亲结点是null
特别注意的是，parent的维护

如果是叶子结点，它的isLeaf的值为true。

初始-树结点

//结点
class TreeNode {//true是黑色，false是红色boolean color;//数据Integer data;TreeNode left;TreeNode right;private static final boolean RED = false;private static final boolean BLACK = true;//是否是叶子结点boolean isLeaf;//方便实现TreeNode parent;public TreeNode() {}public TreeNode(int data) {this.data = data;}public TreeNode(boolean color, Integer data) {this.color = color;this.data = data;}public TreeNode(boolean color, Integer data, TreeNode parent) {this.color = color;this.data = data;this.parent = parent;}public TreeNode(boolean color, Integer data, TreeNode parent, boolean isLeaf) {this.color = color;this.data = data;this.parent = parent;this.isLeaf = isLeaf;}//    public TreeNode(Integer data,TreeNode left, TreeNode right) {
//        this.data = data;
//        this.left = left;
//        this.right = right;
//    }public boolean isBlack() {return color == BLACK;}@Overridepublic String toString() {return "TreeNode{" +"color=" + color +", data=" + data +'}';}}

初始-红黑树

package test;import java.util.LinkedList;
import java.util.Queue;public class RedBlackTree {private static final boolean RED = false;private static final boolean BLACK = true;//根结点TreeNode root;public void initRoot(int data) {root = new TreeNode(BLACK, data, null, false);TreeNode nil = new TreeNode(BLACK, null, root, true);root.left = nil;root.right = nil;}/*** 增加* 1. 父为黑，直接插入* 2. 父叔为红，颜色调换* 3. 父红叔黑，颜色调换，再移动* 4. 父子不同向，先掰直，再执行第3种情况** @param data 数据*/public void add(int data) {}/***  删除* 1.单个红节点  直接删除* 2.单个黑节点*      2.1兄黑*         2.1.1 对侄红 （指方向相反的侄节点）*               父兄交替旋转、然后按父红兄弟黑换色 （最后一步的换色，父红两兄弟黑，是按交替旋转之后的关系处理。）*         2.1.2 顺侄红（指方向相同的侄节点）*              兄侄交替旋转，并调换颜色，就会变成对侄红，然后按2.1.1处理*         2.1.3 双侄黑*              兄变红父变黑，如果父本身就是黑，就以父亲角度按情况2处理**      2.2 兄红*              父兄交替旋转，并调换颜色，新的兄节点将变黑，在按2.1处理* 3.带有一个子节点（当一个节点只有一个子节点时(空叶子除外)，该节点必定是黑节点，其子节点必定是红色）*      用红子节点值替换，然后直接删除红子节点* 4.带有两个子节点!*      找到左子树中最靠右的子节点，用该节点值替换，并删除该节点按情况1，2，3处理（左子树中最大的值，也是离其最近的值)** @param data 数据*/public void delete(int data) {}public static void main(String[] args) {RedBlackTree tree = new RedBlackTree();tree.inorder(tree.root);
//        tree.levelOrder(tree.root);}}

初始-遍历

 //中序遍历public void inorder(TreeNode root) {if (root == null) {return;}if (!root.left.isLeaf) {inorder(root.left);}System.out.println(root);if (!root.right.isLeaf) {inorder(root.right);}}//层序遍历public void levelOrder(TreeNode root) {if (root == null) {return;}Queue<TreeNode> queue = new LinkedList<>();queue.add(root);while (!queue.isEmpty()) {int size = queue.size();for (int i = 0; i < size; i++) {TreeNode cur = queue.poll();System.out.print(cur + "\t");if (cur.left != null) {queue.add(cur.left);}if (cur.right != null) {queue.add(cur.right);}}System.out.println();}}

初始-判断红黑树是否有效

    //判断是否是有效的红黑树public static boolean isValidRedBlackTree(TreeNode root) {if (root == null) {return true;}// 检查根节点是否是黑色if (root.color != BLACK) {return false;}// 计算黑高度，并检查红黑平衡blackHeight = -1;if (!checkBlackBalance(root, 0)) {return false;}// 递归检查每个节点return isValidRedBlackSubtree(root);}private static boolean checkBlackBalance(TreeNode node, int currentBlackHeight) {if (node.isLeaf) {if (blackHeight == -1) {blackHeight = currentBlackHeight;return true;} else {return currentBlackHeight == blackHeight;}}if (node.color == BLACK) {currentBlackHeight++;}return checkBlackBalance(node.left, currentBlackHeight) && checkBlackBalance(node.right, currentBlackHeight);}private static boolean isValidRedBlackSubtree(TreeNode node) {if (node == null) {return true;}// 检查红黑树性质if (node.color == RED) {if ((node.left != null && node.left.color != BLACK) || (node.right != null && node.right.color != BLACK)) {return false;}}// 递归检查左右子树return isValidRedBlackSubtree(node.left) && isValidRedBlackSubtree(node.right);}

查找

 	/*** 查找** @param data 数据* @return 查找结点，如果差不到就会返回叶子结点*/public TreeNode find(int data) {TreeNode find = root;while (!find.isLeaf) {if (data < find.data) {find = find.left;} else if(data==find.data){return find;} else if (data > find.data) {find = find.right;}}return find;}

增加-1.父为黑，直接插入

   /*** 增加* 1. 父为黑，直接插入* 2. 父叔为红，颜色调换* 3. 父红叔黑，颜色调换，再移动* 4. 父子不同向，先掰直，再执行第3种情况** @param data 数据*/public void add(int data) {if (root == null) {initRoot(data);return;}TreeNode find = find(data);if (!find.isLeaf) {System.out.println("不能插入相同数据的结点");return;}TreeNode parent = find.parent;TreeNode newNode = new TreeNode(RED, data, parent);TreeNode nil = new TreeNode(BLACK, null, newNode, true);newNode.left = nil;newNode.right = nil;if (data < parent.data) {parent.left = newNode;} else {parent.right = newNode;}//1.父为黑，直接插入if (parent.isBlack()) {//不需要额外的操作} else {//跳转2...}

增加-2. 父叔为红，颜色调换

    TreeNode grandpa = parent.parent;TreeNode uncle = grandpa.left != parent ? grandpa.left : grandpa.right;//2. 父叔为红，颜色调换if (!uncle.isBlack()) {parent.color = BLACK;uncle.color = BLACK;grandpa.color = RED;//如果爷爷是根节点if (grandpa == root) {grandpa.color = BLACK;return;}//爷爷变成红色后，它的父叔可能为红TreeNode cur=grandpa;parent=cur.parent;grandpa=parent.parent;if (parent==null||grandpa==null){return;}uncle=grandpa.left != parent ? grandpa.left : grandpa.right;while (!cur.isBlack()&&!parent.isBlack()&&!uncle.isBlack()){parent.color = BLACK;uncle.color = BLACK;grandpa.color = RED;//如果爷爷是根节点if (grandpa == root) {grandpa.color = BLACK;break;}cur=grandpa;parent=cur.parent;grandpa=parent.parent;uncle=grandpa.left != parent ? grandpa.left : grandpa.right;}} else {//跳转3...}

增加-3. 父红叔黑，颜色调换，再移动

//跳转3...boolean right1 = data > parent.data;boolean right2 = parent.data > grandpa.data;boolean direct1 = right1 && right2;boolean left1 = data < parent.data;boolean left2 = parent.data < grandpa.data;boolean direct2 = left1 && left2;//3. 父红叔黑，颜色调换，再移动if (direct1 || direct2) {op(data, parent, grandpa);} else {//跳转4...}public void op(int data, TreeNode parent, TreeNode grandpa) {boolean right1 = data > parent.data;boolean right2 = parent.data > grandpa.data;boolean direct1 = right1 && right2;boolean left1 = data < parent.data;boolean left2 = parent.data < grandpa.data;boolean direct2 = left1 && left2;boolean tmp = grandpa.color;grandpa.color = parent.color;parent.color = tmp;TreeNode grandpaPa = grandpa.parent;if (parent.data < grandpaPa.data) {grandpaPa.left = parent;} else {grandpaPa.right = parent;}parent.parent = grandpaPa;if (direct1) {parent.left = grandpa;grandpa.parent = parent;} else if (direct2) {parent.right = grandpa;grandpa.parent = parent;}grandpa.left = new TreeNode(BLACK, null, grandpa, true);grandpa.right = new TreeNode(BLACK, null, grandpa, true);}

增加-4. 父子不同向，先掰直，再执行第3种情况

					//跳转4...//4. 父子不同向，先掰直，再执行第3种情况if (left1) {grandpa.right = newNode;newNode.right = parent;}if (right1) {grandpa.left = newNode;newNode.left = parent;}newNode.parent = grandpa;parent.parent = newNode;TreeNode newNil = new TreeNode(BLACK, null, parent, true);parent.left = newNil;parent.right = newNil;op(parent.data, newNode, grandpa);

测试增加

    public static void main(String[] args) {RedBlackTree tree = new RedBlackTree();testAdd(tree);}private static void testAdd(RedBlackTree tree) {tree.add(157);//0tree.add(12);//1tree.add(200);//1tree.add(250);//2tree.add(260);//3tree.add(220);//2tree.add(210);//4tree.add(11);//1tree.add(10);//3tree.add(7);//2tree.add(9);//4tree.inorder(tree.root);
//        tree.levelOrder(tree.root);System.out.println(isValidRedBlackTree(tree.root));}

11、10、7、9的插入图如下

2024-3-30 15:35:56

删除-0 初始化数据

    public static void main(String[] args) {RedBlackTree tree = new RedBlackTree();
//        testAdd(tree);initData(tree);}private static void initData(RedBlackTree tree) {int[] nums={430,261,636,95,344,559,822,37,131,330,369,499,594,705,981,262,345,485,664,818};for (int i = 0; i < nums.length; i++) {tree.add(nums[i]);}//        tree.inorder(tree.root);tree.levelOrder(tree.root);System.out.println(isValidRedBlackTree(tree.root));}

删除-1.单个红节点 直接删除

 /***  删除* 1.单个红节点  直接删除* 2.单个黑节点*      2.1兄黑*         2.1.1 对侄红 （指方向相反的侄节点）*               父兄交替旋转、然后按父红兄弟黑换色 （最后一步的换色，父红两兄弟黑，是按交替旋转之后的关系处理。）*         2.1.2 顺侄红（指方向相同的侄节点）*              兄侄交替旋转，并调换颜色，就会变成对侄红，然后按2.1.1处理*         2.1.3 双侄黑*              兄变红父变黑，如果父本身就是黑，就以父亲角度按情况2处理**      2.2 兄红*              父兄交替旋转，并调换颜色，新的兄节点将变黑，在按2.1处理* 3.带有一个子节点（当一个节点只有一个子节点时(空叶子除外)，该节点必定是黑节点，其子节点必定是红色）*      用红子节点值替换，然后直接删除红子节点* 4.带有两个子节点*      找到左子树中最靠右的子节点，用该节点值替换，并删除该节点按情况1，2，3处理（左子树中最大的值，也是离其最近的值)** @param data 数据*/public void delete(int data) {TreeNode find = find(data);if (find.isLeaf){System.out.println("没有找到");return;}//1.单个红节点if (!find.isBlack()){if (find.left.isLeaf&&find.right.isLeaf){TreeNode parent = find.parent;TreeNode nil=new TreeNode(BLACK,null,parent,true);if (data<parent.data){parent.left=nil;}else {parent.right=nil;}}else {//4.带有两个子节点}}else {//3.带有一个子节点,用红子节点值替换，然后直接删除红子节点}}

删除-3.带有一个子节点

			//3.带有一个子节点,用红子节点值替换，然后直接删除红子节点if (find.left.isLeaf&&!find.right.isBlack()){find.data=find.right.data;find.right= new TreeNode(BLACK,null,find,true);}else if (find.right.isLeaf&&!find.left.isBlack()){find.data=find.left.data;find.left= new TreeNode(BLACK,null,find,true);} 

删除-4.带有两个子节点

			else if (!find.left.isLeaf&&!find.right.isLeaf){//4.带有两个子节点TreeNode replace = findReplace(find);delete(replace.data);find.data= replace.data;}else {//2.单个黑结点/*** 查找替代的结点* 中序遍历线索树的直接前驱结点* @param node 删除的结点* @return 查找替代*/public TreeNode findReplace(TreeNode node) {TreeNode left = node.left;while (!left.isLeaf) {left=left.right;}return left.parent;}

删除-2.单个黑结点

2.1.1兄黑，对侄红

  				TreeNode parent=find.parent;TreeNode brother=parent.left!=find?parent.left:parent.right;boolean left=find.data<parent.data;//对侄TreeNode duiNephew=left?brother.right:brother.left;//顺侄TreeNode shunNephew=left?brother.left:brother.right;if (brother.isBlack()){//2.1兄黑//2.1.1 对侄红TreeNode duiNephew=left?brother.right:brother.left;if (!duiNephew.isBlack()){//父兄交替旋转TreeNode grandpa=parent.parent;if (brother.data<grandpa.data){grandpa.left=brother;}else {grandpa.right=brother;}brother.parent=grandpa;if (left){brother.left=parent;}else {brother.right=parent;}parent.parent=brother;TreeNode nil=new TreeNode(BLACK,null,parent,true);parent.left=nil;parent.right=nil;//并调换颜色brother.color=RED;duiNephew.color=BLACK;parent.color=BLACK;}else if (!shunNephew.isBlack()){//2.1.2 顺侄红}else if (brother.left.isBlack()&&brother.right.isBlack()){//2.1.3 双侄黑}else{//兄红}

2.1.2兄黑，顺侄红

                        //兄侄交替旋转，并调换颜色，就会变成对侄红，if (brother.data< parent.data){parent.left=shunNephew;shunNephew.left=brother;}else {parent.right=shunNephew;shunNephew.right=brother;}shunNephew.parent=parent;brother.parent=shunNephew;TreeNode nil=new TreeNode(BLACK,null,brother,true);brother.left=nil;brother.right=nil;brother.color=RED;shunNephew.color=BLACK;delete(data);

2.1.3 兄黑，双侄黑

                        //兄变红父变黑，如果父本身就是黑，就以父亲角度按情况2处理brother.color=RED;parent.color=BLACK;TreeNode nil=new TreeNode(BLACK,null,parent,true);if (find.data< parent.data){parent.left=nil;}else {parent.right=nil;}

删除-2.单个黑结点 2.2兄红

					//父兄交替旋转，并调换颜色，新的兄节点将变黑，在按2.1处理TreeNode grandpa=parent.parent;if (brother.data<grandpa.data){grandpa.left=brother;}else {grandpa.right=brother;}brother.parent=grandpa;TreeNode tmp;if (data<parent.data){tmp=brother.left;brother.left=parent;}else {tmp=brother.right;brother.right=parent;}parent.parent=brother;if (data<parent.data){parent.left=find;parent.right=tmp;}else {parent.left=tmp;parent.right=find;}brother.color=BLACK;parent.color=RED;delete(data);

测试删除

    public static void main(String[] args) {RedBlackTree tree = new RedBlackTree();
//        testAdd(tree);initData(tree);testDelete(tree);tree.levelOrder(tree.root);System.out.println(isValidRedBlackTree(tree.root));}private static void testDelete(RedBlackTree tree) {tree.delete(262);//1tree.delete(818);//1tree.delete(705);//3tree.delete(369);//3tree.add(346);tree.delete(430);//4tree.delete(594);//2.1.1tree.add(570);tree.delete(485);//2.1.1tree.add(565);tree.delete(499);//2.1.2tree.add(335);tree.delete(345);//2.1.2tree.delete(559);//2.1.3tree.delete(570);tree.delete(565);//2.2tree.delete(37);tree.delete(131);tree.delete(95);//2.2}

附录源码

package test;import java.util.LinkedList;
import java.util.Queue;public class RedBlackTree {private static final boolean RED = false;private static final boolean BLACK = true;//根结点TreeNode root;public void initRoot(int data) {root = new TreeNode(BLACK, data, null, false);TreeNode nil = new TreeNode(BLACK, null, root, true);root.left = nil;root.right = nil;}/*** 增加* 1. 父为黑，直接插入* 2. 父叔为红，颜色调换* 3. 父红叔黑，颜色调换，再移动* 4. 父子不同向，先掰直，再执行第3种情况** @param data 数据*/public void add(int data) {if (root == null) {initRoot(data);return;}TreeNode find = find(data);if (!find.isLeaf) {System.out.println("不能插入相同数据的结点");return;}TreeNode parent = find.parent;TreeNode newNode = new TreeNode(RED, data, parent);TreeNode nil = new TreeNode(BLACK, null, newNode, true);newNode.left = nil;newNode.right = nil;if (data < parent.data) {parent.left = newNode;} else {parent.right = newNode;}//1.父为黑，直接插入if (parent.isBlack()) {//不需要额外的操作} else {TreeNode grandpa = parent.parent;TreeNode uncle = grandpa.left != parent ? grandpa.left : grandpa.right;//2. 父叔为红，颜色调换if (!uncle.isBlack()) {parent.color = BLACK;uncle.color = BLACK;grandpa.color = RED;//如果爷爷是根节点if (grandpa == root) {grandpa.color = BLACK;return;}//爷爷变成红色后，它的父叔可能为红TreeNode cur=grandpa;parent=cur.parent;grandpa=parent.parent;if (parent==null||grandpa==null){return;}uncle=grandpa.left != parent ? grandpa.left : grandpa.right;while (!cur.isBlack()&&!parent.isBlack()&&!uncle.isBlack()){parent.color = BLACK;uncle.color = BLACK;grandpa.color = RED;//如果爷爷是根节点if (grandpa == root) {grandpa.color = BLACK;break;}cur=grandpa;parent=cur.parent;grandpa=parent.parent;uncle=grandpa.left != parent ? grandpa.left : grandpa.right;}} else {boolean right1 = data > parent.data;boolean right2 = parent.data > grandpa.data;boolean direct1 = right1 && right2;boolean left1 = data < parent.data;boolean left2 = parent.data < grandpa.data;boolean direct2 = left1 && left2;//3. 父红叔黑，颜色调换，再移动if (direct1 || direct2) {op(data, parent, grandpa);} else {//4. 父子不同向，先掰直，再执行第3种情况if (left1) {grandpa.right = newNode;newNode.right = parent;}if (right1) {grandpa.left = newNode;newNode.left = parent;}newNode.parent = grandpa;parent.parent = newNode;TreeNode newNil = new TreeNode(BLACK, null, parent, true);parent.left = newNil;parent.right = newNil;op(parent.data, newNode, grandpa);}}}}public void op(int data, TreeNode parent, TreeNode grandpa) {boolean right1 = data > parent.data;boolean right2 = parent.data > grandpa.data;boolean direct1 = right1 && right2;boolean left1 = data < parent.data;boolean left2 = parent.data < grandpa.data;boolean direct2 = left1 && left2;boolean tmp = grandpa.color;grandpa.color = parent.color;parent.color = tmp;TreeNode grandpaPa = grandpa.parent;if (parent.data < grandpaPa.data) {grandpaPa.left = parent;} else {grandpaPa.right = parent;}parent.parent = grandpaPa;if (direct1) {parent.left = grandpa;grandpa.parent = parent;} else if (direct2) {parent.right = grandpa;grandpa.parent = parent;}grandpa.left = new TreeNode(BLACK, null, grandpa, true);grandpa.right = new TreeNode(BLACK, null, grandpa, true);}/***  删除* 1.单个红节点  直接删除* 2.单个黑节点*      2.1兄黑*         2.1.1 对侄红 （指方向相反的侄节点）*               父兄交替旋转、然后按父红兄弟黑换色 （最后一步的换色，父红两兄弟黑，是按交替旋转之后的关系处理。）*         2.1.2 顺侄红（指方向相同的侄节点）*              兄侄交替旋转，并调换颜色，就会变成对侄红，然后按2.1.1处理*         2.1.3 双侄黑*              兄变红父变黑，如果父本身就是黑，就以父亲角度按情况2处理**      2.2 兄红*              父兄交替旋转，并调换颜色，新的兄节点将变黑，在按2.1处理* 3.带有一个子节点（当一个节点只有一个子节点时(空叶子除外)，该节点必定是黑节点，其子节点必定是红色）*      用红子节点值替换，然后直接删除红子节点* 4.带有两个子节点*      找到左子树中最靠右的子节点，用该节点值替换，并删除该节点按情况1，2，3处理（左子树中最大的值，也是离其最近的值)** @param data 数据*/public void delete(int data) {TreeNode find = find(data);if (find.isLeaf){System.out.println("没有找到");return;}//1.单个红节点if (!find.isBlack()){if (find.left.isLeaf&&find.right.isLeaf){TreeNode parent = find.parent;TreeNode nil=new TreeNode(BLACK,null,parent,true);if (data<parent.data){parent.left=nil;}else {parent.right=nil;}}else {//4.带有两个子节点TreeNode replace = findReplace(find);delete(replace.data);find.data= replace.data;}}else {//3.带有一个子节点,用红子节点值替换，然后直接删除红子节点if (find.left.isLeaf&&!find.right.isBlack()){find.data=find.right.data;find.right= new TreeNode(BLACK,null,find,true);}else if (find.right.isLeaf&&!find.left.isBlack()){find.data=find.left.data;find.left= new TreeNode(BLACK,null,find,true);} else if (!find.left.isLeaf&&!find.right.isLeaf){//4.带有两个子节点TreeNode replace = findReplace(find);delete(replace.data);find.data= replace.data;}else {//2.单个黑结点TreeNode parent=find.parent;TreeNode brother=parent.left!=find?parent.left:parent.right;boolean left=find.data<parent.data;//对侄TreeNode duiNephew=left?brother.right:brother.left;//顺侄TreeNode shunNephew=left?brother.left:brother.right;if (brother.isBlack()){//2.1兄黑//2.1.1 对侄红if (!duiNephew.isBlack()){//父兄交替旋转TreeNode grandpa=parent.parent;if (brother.data<grandpa.data){grandpa.left=brother;}else {grandpa.right=brother;}brother.parent=grandpa;if (left){brother.left=parent;}else {brother.right=parent;}parent.parent=brother;TreeNode nil=new TreeNode(BLACK,null,parent,true);parent.left=nil;parent.right=nil;//并调换颜色brother.color=RED;duiNephew.color=BLACK;parent.color=BLACK;} else if (!shunNephew.isBlack()){//2.1.2 顺侄红//兄侄交替旋转，并调换颜色，就会变成对侄红，if (brother.data< parent.data){parent.left=shunNephew;shunNephew.left=brother;}else {parent.right=shunNephew;shunNephew.right=brother;}shunNephew.parent=parent;brother.parent=shunNephew;TreeNode nil=new TreeNode(BLACK,null,brother,true);brother.left=nil;brother.right=nil;brother.color=RED;shunNephew.color=BLACK;delete(data);} else if (brother.left.isBlack()&&brother.right.isBlack()){//2.1.3 双侄黑//兄变红父变黑，如果父本身就是黑，就以父亲角度按情况2处理brother.color=RED;parent.color=BLACK;TreeNode nil=new TreeNode(BLACK,null,parent,true);if (find.data< parent.data){parent.left=nil;}else {parent.right=nil;}}}else {//2.2兄红//父兄交替旋转，并调换颜色，新的兄节点将变黑，在按2.1处理TreeNode grandpa=parent.parent;if (brother.data<grandpa.data){grandpa.left=brother;}else {grandpa.right=brother;}brother.parent=grandpa;TreeNode tmp;if (data<parent.data){tmp=brother.left;brother.left=parent;}else {tmp=brother.right;brother.right=parent;}parent.parent=brother;if (data<parent.data){parent.left=find;parent.right=tmp;}else {parent.left=tmp;parent.right=find;}brother.color=BLACK;parent.color=RED;delete(data);}}}}/*** 查找** @param data 数据* @return 查找结点，如果差不到就会返回叶子结点*/public TreeNode find(int data) {TreeNode find = root;while (!find.isLeaf) {if (data < find.data) {find = find.left;} else if(find.data.equals(data)){return find;} else if (data > find.data) {find = find.right;}}return find;}/*** 查找替代的结点* 中序遍历线索树的直接前驱结点* @param node 删除的结点* @return 查找替代*/public TreeNode findReplace(TreeNode node) {TreeNode left = node.left;while (!left.isLeaf) {left=left.right;}return left.parent;}//中序遍历public void inorder(TreeNode root) {if (root == null) {return;}if (!root.left.isLeaf) {inorder(root.left);}System.out.println(root);if (!root.right.isLeaf) {inorder(root.right);}}//层序遍历public void levelOrder(TreeNode root) {if (root == null) {return;}Queue<TreeNode> queue = new LinkedList<>();queue.add(root);while (!queue.isEmpty()) {int size = queue.size();for (int i = 0; i < size; i++) {TreeNode cur = queue.poll();System.out.print(cur + "\t");if (cur.left != null) {queue.add(cur.left);}if (cur.right != null) {queue.add(cur.right);}}System.out.println();}}private static int blackHeight = -1;//判断是否是有效的红黑树public static boolean isValidRedBlackTree(TreeNode root) {if (root == null) {return true;}// 检查根节点是否是黑色if (root.color != BLACK) {return false;}// 计算黑高度，并检查红黑平衡blackHeight = -1;if (!checkBlackBalance(root, 0)) {return false;}// 递归检查每个节点return isValidRedBlackSubtree(root);}private static boolean checkBlackBalance(TreeNode node, int currentBlackHeight) {if (node.isLeaf) {if (blackHeight == -1) {blackHeight = currentBlackHeight;return true;} else {return currentBlackHeight == blackHeight;}}if (node.color == BLACK) {currentBlackHeight++;}return checkBlackBalance(node.left, currentBlackHeight) && checkBlackBalance(node.right, currentBlackHeight);}private static boolean isValidRedBlackSubtree(TreeNode node) {if (node == null) {return true;}// 检查红黑树性质if (node.color == RED) {if ((node.left != null && node.left.color != BLACK) || (node.right != null && node.right.color != BLACK)) {return false;}}// 递归检查左右子树return isValidRedBlackSubtree(node.left) && isValidRedBlackSubtree(node.right);}public static void main(String[] args) {RedBlackTree tree = new RedBlackTree();
//        testAdd(tree);initData(tree);testDelete(tree);tree.levelOrder(tree.root);System.out.println(isValidRedBlackTree(tree.root));}private static void testDelete(RedBlackTree tree) {tree.delete(262);//1tree.delete(818);//1tree.delete(705);//3tree.delete(369);//3tree.add(346);tree.delete(430);//4tree.delete(594);//2.1.1tree.add(570);tree.delete(485);//2.1.1tree.add(565);tree.delete(499);//2.1.2tree.add(335);tree.delete(345);//2.1.2tree.delete(559);//2.1.3tree.delete(570);tree.delete(565);//2.2tree.delete(37);tree.delete(131);tree.delete(95);//2.2}private static void initData(RedBlackTree tree) {int[] nums={430,261,636,95,344,559,822,37,131,330,369,499,594,705,981,262,345,485,664,818};for (int i = 0; i < nums.length; i++) {tree.add(nums[i]);}//        tree.inorder(tree.root);
//        tree.levelOrder(tree.root);
//        System.out.println(isValidRedBlackTree(tree.root));}private static void testAdd(RedBlackTree tree) {tree.add(157);//0tree.add(12);//1tree.add(200);//1tree.add(250);//2tree.add(260);//3tree.add(220);//2tree.add(210);//4tree.add(11);//1tree.add(10);//3tree.add(7);//2tree.add(9);//4tree.inorder(tree.root);
//        tree.levelOrder(tree.root);System.out.println(isValidRedBlackTree(tree.root));}}//结点
class TreeNode {//true是黑色，false是红色boolean color;//数据Integer data;TreeNode left;TreeNode right;private static final boolean RED = false;private static final boolean BLACK = true;//是否是叶子结点boolean isLeaf;//方便实现TreeNode parent;public TreeNode() {}public TreeNode(int data) {this.data = data;}public TreeNode(boolean color, Integer data) {this.color = color;this.data = data;}public TreeNode(boolean color, Integer data, TreeNode parent) {this.color = color;this.data = data;this.parent = parent;}public TreeNode(boolean color, Integer data, TreeNode parent, boolean isLeaf) {this.color = color;this.data = data;this.parent = parent;this.isLeaf = isLeaf;}//    public TreeNode(Integer data,TreeNode left, TreeNode right) {
//        this.data = data;
//        this.left = left;
//        this.right = right;
//    }public boolean isBlack() {return color == BLACK;}@Overridepublic String toString() {return "TreeNode{" +"color=" + color +", data=" + data +'}';}}

最后

2024-3-30 23:05:13

写了一天

迎着日光月光星光，直面风霜雨霜雪霜。