用java举一个红黑树的例子

以下是一个用Java实现的红黑树示例：

class Node {
    int value;
    Node parent;
    Node left;
    Node right;
    boolean isRed;

    public Node(int value, Node parent, Node left, Node right, boolean isRed) {
        this.value = value;
        this.parent = parent;
        this.left = left;
        this.right = right;
        this.isRed = isRed;
    }
}

public class RedBlackTree {
    private Node root;

    public void insert(int value) {
        Node newNode = new Node(value, null, null, null, true);
        if (root == null) {
            root = newNode;
        } else {
            Node current = root;
            Node parent = null;
            while (true) {
                parent = current;
                if (value < current.value) {
                    current = current.left;
                    if (current == null) {
                        parent.left = newNode;
                        newNode.parent = parent;
                        fixRedBlackTree(newNode);
                        return;
                    }
                } else {
                    current = current.right;
                    if (current == null) {
                        parent.right = newNode;
                        newNode.parent = parent;
                        fixRedBlackTree(newNode);
                        return;
                    }
                }
            }
        }
    }

    private void fixRedBlackTree(Node node) {
        while (node.parent != null && node.parent.isRed) {
            Node parent = node.parent;
            Node grandParent = parent.parent;
            if (parent == grandParent.left) {
                Node uncle = grandParent.right;
                if (uncle != null && uncle.isRed) {
                    grandParent.isRed = true;
                    parent.isRed = false;
                    uncle.isRed = false;
                    node = grandParent;
                } else {
                    if (node == parent.right) {
                        rotateLeft(parent);
                        node = parent;
                        parent = node.parent;
                    }
                    parent.isRed = false;
                    grandParent.isRed = true;
                    rotateRight(grandParent);
                }
            } else {
                Node uncle = grandParent.left;
                if (uncle != null && uncle.isRed) {
                    grandParent.isRed = true;
                    parent.isRed = false;
                    uncle.isRed = false;
                    node = grandParent;
                } else {
                    if (node == parent.left) {
                        rotateRight(parent);
                        node = parent;
                        parent = node.parent;
                    }
                    parent.isRed = false;
                    grandParent.isRed = true;
                    rotateLeft(grandParent);
                }
            }
        }
        root.isRed = false;
    }

    private void rotateLeft(Node node) {
        Node rightChild = node.right;
        node.right = rightChild.left;
        if (rightChild.left != null) {
            rightChild.left.parent = node;
        }
        rightChild.parent = node.parent;
        if (node.parent == null) {
            root = rightChild;
        } else if (node == node.parent.left) {
            node.parent.left = rightChild;
        } else {
            node.parent.right = rightChild;
        }
        rightChild.left = node;
        node.parent = rightChild;
    }

    private void rotateRight(Node node) {
        Node leftChild = node.left;
        node.left = leftChild.right;
        if (leftChild.right != null) {
            leftChild.right.parent = node;
        }
        leftChild.parent = node.parent;
        if (node.parent == null) {
            root = leftChild;
        } else if (node == node.parent.right) {
            node.parent.right = leftChild;
        } else {
            node.parent.left = leftChild;
        }
        leftChild.right = node;
        node.parent = leftChild;
    }
}

这段代码实现了红黑树的插入操作，并且在插入后保证了红黑树的性质。在插入新节点后，如果发现需要调整红黑树，就会执行 `fixRedBlackTree` 方法来进行调整。该方法使用了红黑树的调整规则，包括左旋、右旋和变色操作。