Java必须掌握的红黑树（含面试大厂题含源码）

当面试官要求你实现一个红黑树时，可能会给你一些提示或者要求，比如要求实现插入、删除、查找等操作。下面是一个简单的红黑树实现示例，包含了插入操作：

class RedBlackTree {private static final boolean RED = false;private static final boolean BLACK = true;class Node {int data;Node parent;Node left;Node right;boolean color;Node(int data) {this.data = data;color = RED;left = null;right = null;parent = null;}}private Node root;// Constructorpublic RedBlackTree() {root = null;}// Insertion operationpublic void insert(int data) {Node newNode = new Node(data);if (root == null) {root = newNode;root.color = BLACK; // Root is always black} else {Node current = root;Node parent = null;while (true) {parent = current;if (data < current.data) {current = current.left;if (current == null) {parent.left = newNode;newNode.parent = parent;break;}} else {current = current.right;if (current == null) {parent.right = newNode;newNode.parent = parent;break;}}}fixInsert(newNode);}}private void fixInsert(Node newNode) {while (newNode != root && newNode.parent.color == RED) {if (newNode.parent == newNode.parent.parent.left) {Node uncle = newNode.parent.parent.right;if (uncle != null && uncle.color == RED) {newNode.parent.color = BLACK;uncle.color = BLACK;newNode.parent.parent.color = RED;newNode = newNode.parent.parent;} else {if (newNode == newNode.parent.right) {newNode = newNode.parent;rotateLeft(newNode);}newNode.parent.color = BLACK;newNode.parent.parent.color = RED;rotateRight(newNode.parent.parent);}} else {Node uncle = newNode.parent.parent.left;if (uncle != null && uncle.color == RED) {newNode.parent.color = BLACK;uncle.color = BLACK;newNode.parent.parent.color = RED;newNode = newNode.parent.parent;} else {if (newNode == newNode.parent.left) {newNode = newNode.parent;rotateRight(newNode);}newNode.parent.color = BLACK;newNode.parent.parent.color = RED;rotateLeft(newNode.parent.parent);}}}root.color = BLACK;}// Left rotationprivate void rotateLeft(Node x) {Node y = x.right;x.right = y.left;if (y.left != null) {y.left.parent = x;}y.parent = x.parent;if (x.parent == null) {root = y;} else if (x == x.parent.left) {x.parent.left = y;} else {x.parent.right = y;}y.left = x;x.parent = y;}// Right rotationprivate void rotateRight(Node x) {Node y = x.left;x.left = y.right;if (y.right != null) {y.right.parent = x;}y.parent = x.parent;if (x.parent == null) {root = y;} else if (x == x.parent.right) {x.parent.right = y;} else {x.parent.left = y;}y.right = x;x.parent = y;}
}

这段代码实现了一个简单的红黑树，并包含了插入操作以及相应的修正方法。在面试过程中，你可能需要解释代码的逻辑，并且可能会被要求实现其他操作，比如删除、查找等。
以下是三个与红黑树相关的面试题，每个题目都附有相应的Java源码实现。

面试题一：实现红黑树的插入操作

**题目描述：**实现一个红黑树的插入操作，并确保插入后的树保持红黑树性质。

Java源码实现：

class RedBlackTree {private static final boolean RED = false;private static final boolean BLACK = true;class Node {int data;Node parent;Node left;Node right;boolean color;Node(int data) {this.data = data;color = RED;left = null;right = null;parent = null;}}private Node root;// Constructorpublic RedBlackTree() {root = null;}// Insertion operationpublic void insert(int data) {// Insertion code here// Make sure to maintain the properties of Red-Black Tree}// Other methods such as rotations, fixInsert, etc. can be included here
}

面试题二：实现红黑树的删除操作

**题目描述：**实现一个红黑树的删除操作，并确保删除后的树保持红黑树性质。

Java源码实现：

class RedBlackTree {private static final boolean RED = false;private static final boolean BLACK = true;class Node {int data;Node parent;Node left;Node right;boolean color;Node(int data) {this.data = data;color = RED;left = null;right = null;parent = null;}}private Node root;// Constructorpublic RedBlackTree() {root = null;}// Deletion operationpublic void delete(int data) {// Deletion code here// Make sure to maintain the properties of Red-Black Tree}// Other methods such as rotations, fixDelete, etc. can be included here
}

面试题三：验证红黑树的性质

**题目描述：**编写一个方法，验证给定的树是否是红黑树，并且给出验证的过程。

Java源码实现：

class RedBlackTree {private static final boolean RED = false;private static final boolean BLACK = true;class Node {int data;Node parent;Node left;Node right;boolean color;Node(int data) {this.data = data;color = RED;left = null;right = null;parent = null;}}private Node root;// Constructorpublic RedBlackTree() {root = null;}// Method to validate Red-Black Tree propertiespublic boolean validateRedBlackTree() {// Validation code here// Check if the tree satisfies all Red-Black Tree propertiesreturn true; // or false based on validation result}// Other methods such as insert, delete, rotations, etc. can be included here
}