紅黑樹是一種自平衡的二叉查找樹,可以在O(log n)的時間復雜度內進行插入、刪除和查找操作。以下是一個簡單的C++實現紅黑樹的算法:
#include <iostream>
using namespace std;
enum Color { RED, BLACK };
struct Node {
int data;
Color color;
Node *left, *right, *parent;
Node(int data) : data(data) {
parent = left = right = NULL;
color = RED;
}
};
class RedBlackTree {
private:
Node *root;
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;
}
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->left) {
x->parent->left = y;
} else {
x->parent->right = y;
}
y->right = x;
x->parent = y;
}
void fixViolation(Node *x) {
Node *parent = NULL;
Node *grandparent = NULL;
while (x != root && x->color == RED && x->parent->color == RED) {
parent = x->parent;
grandparent = x->parent->parent;
if (parent == grandparent->left) {
Node *uncle = grandparent->right;
if (uncle != NULL && uncle->color == RED) {
grandparent->color = RED;
parent->color = BLACK;
uncle->color = BLACK;
x = grandparent;
} else {
if (x == parent->right) {
rotateLeft(parent);
x = parent;
parent = x->parent;
}
rotateRight(grandparent);
swap(parent->color, grandparent->color);
x = parent;
}
} else {
Node *uncle = grandparent->left;
if (uncle != NULL && uncle->color == RED) {
grandparent->color = RED;
parent->color = BLACK;
uncle->color = BLACK;
x = grandparent;
} else {
if (x == parent->left) {
rotateRight(parent);
x = parent;
parent = x->parent;
}
rotateLeft(grandparent);
swap(parent->color, grandparent->color);
x = parent;
}
}
}
root->color = BLACK;
}
void insertHelper(Node *node) {
Node *cur = root;
Node *parent = NULL;
while (cur != NULL) {
parent = cur;
if (node->data < cur->data) {
cur = cur->left;
} else {
cur = cur->right;
}
}
node->parent = parent;
if (parent == NULL) {
root = node;
} else if (node->data < parent->data) {
parent->left = node;
} else {
parent->right = node;
}
fixViolation(node);
}
void inorderHelper(Node *node) {
if (node == NULL) {
return;
}
inorderHelper(node->left);
cout << node->data << " ";
inorderHelper(node->right);
}
public:
RedBlackTree() : root(NULL) {}
void insert(int data) {
Node *node = new Node(data);
insertHelper(node);
}
void inorder() {
inorderHelper(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);
cout << "Inorder traversal of the constructed Red-Black tree is: ";
tree.inorder();
return 0;
}