c++实现一个红黑树

红黑树是一种自平衡的二叉搜索，它具有以下特性：
1. 每个节点要么是红色，要么是黑色。
2. 根节点是黑色的。
3. 每个叶子节点（NIL节点，空节点）是黑色的。
4. 如果一个节点是红色的，则它的两个子节点都是黑色的。
5. 对于每个节点，从该节点到其所有后代叶子节点的简单路径上，均包含相同数目的黑色节点。

下面是一个简单的C++实现红黑树的示例：

#include <iostream>

enum Color { RED, BLACK };

struct Node {
    int data;
    Color color;
    Node* left;
    Node* right;
    Node* parent;

    Node(int data) : data(data), color(RED), left(nullptr), right(nullptr), parent(nullptr) {}
};

class RedBlackTree {
private:
    Node* root;

    void rotateLeft(Node* node) {
        Node* rightChild = node->right;
        node->right = rightChild->left;

        if (rightChild->left != nullptr) {
            rightChild->left->parent = node;
        }

        rightChild->parent = node->parent;

        if (node->parent == nullptr) {
            root = rightChild;
        } else if (node == node->parent->left) {
            node->parent->left = rightChild;
        } else {
            node->parent->right = rightChild;
        }

        rightChild->left = node;
        node->parent = rightChild;
    }

    void rotateRight(Node* node) {
        Node* leftChild = node->left;
        node->left = leftChild->right;

        if (leftChild->right != nullptr) {
            leftChild->right->parent = node;
        }

        leftChild->parent = node->parent;

        if (node->parent == nullptr) {
            root = leftChild;
        } else if (node == node->parent->left) {
            node->parent->left = leftChild;
        } else {
            node->parent->right = leftChild;
        }

        leftChild->right = node;
        node->parent = leftChild;
    }

    void fixInsert(Node* node) {
        while (node != root && node->parent->color == RED) {
            if (node->parent == node->parent->parent->left) {
                Node* uncle = node->parent->parent->right;

                if (uncle != nullptr && uncle->color == RED) {
                    node->parent->color = BLACK;
                    uncle->color = BLACK;
                    node->parent->parent->color = RED;
                    node = node->parent->parent;
                } else {
                    if (node == node->parent->right) {
                        node = node->parent;
                        rotateLeft(node);
                    }

                    node->parent->color = BLACK;
                    node->parent->parent->color = RED;
                    rotateRight(node->parent->parent);
                }
            } else {
                Node* uncle = node->parent->parent->left;

                if (uncle != nullptr && uncle->color == RED) {
                    node->parent->color = BLACK;
                    uncle->color = BLACK;
                    node->parent->parent->color = RED;
                    node = node->parent->parent;
                } else {
                    if (node == node->parent->left) {
                        node = node->parent;
                        rotateRight(node);
                    }

                    node->parent->color = BLACK;
                    node->parent->parent->color = RED;
                    rotateLeft(node->parent->parent);
                }
            }
        }

        root->color = BLACK;
    }

public:
    RedBlackTree() : root(nullptr) {}

    void insert(int data) {
        Node* newNode = new Node(data);
        Node* current = root;
        Node* parent = nullptr;

        while (current != nullptr) {
            parent = current;

            if (data < current->data) {
                current = current->left;
            } else {
                current = current->right;
            }
        }

        newNode->parent = parent;

        if (parent == nullptr) {
            root = newNode;
        } else if (data < parent->data) {
            parent->left = newNode;
        } else {
            parent->right = newNode;
        }

        fixInsert(newNode);
    }

    void printInorder(Node* node) {
        if (node == nullptr) {
            return;
        }

        printInorder(node->left);
        std::cout << node->data << " ";
        printInorder(node->right);
    }

    void printTree() {
        printInorder(root);
    }
};

int main() {
    RedBlackTree tree;

    tree.insert(7);
    tree.insert(3);
    tree.insert(18);
    tree.insert(10);
    tree.insert(22);
    tree.insert(8);
    tree.insert(11);
    tree.insert(26);
    tree.insert(2);
    tree.insert(6);
    tree.insert(13);

    std::cout << "Red-Black Tree: ";
    tree.printTree();

    return 0;
}

这个示例实现了红黑树的插入操作，并且打印出了树的中序遍历结果。