AVL Tree(C++模板实现)

#include 
using namespace std;
template<typename T>
struct Node
{
    T key;
    Node *left, *right;
    Node(const T &k):key(k),left(nullptr),right(nullptr){}
};
template<typename T>
class AVLTree
{
public:
    AVLTree<T>(){root=nullptr;}
private:
    Node<T> *root;
    inline int getHeight(Node<T> *node);
    inline int getBalance(Node<T> *node);
    inline Node<T>* rotationLeft(Node<T> *node);
    inline Node<T>* rotationRight(Node<T> *node);
    inline Node<T>* successor(Node<T> *node);
    inline void inOrder(Node<T> *node);
    inline void preOrder(Node<T> *node);
    Node<T>* put(Node<T>* &node, const T &key);
    Node<T>* del(Node<T> *node, const T &key);
public:
    inline void put(const T &key);
    inline void del(const T &key);
    inline void inOrder();
    inline void preOrder();
};
template<typename T>
inline int AVLTree<T>::getHeight(Node<T> *node)
{
    if(node == nullptr)
        return -1;
    return max(getHeight(node->left), getHeight(node->right)) + 1;
}
template<typename T>
inline int AVLTree<T>::getBalance(Node<T> *node)
{
    if(node == nullptr)
        return 0;
    return getHeight(node->left) - getHeight(node->right);
}
template<typename T>
inline Node<T>* AVLTree<T>::rotationLeft(Node<T>* x)
{
    Node<T> *y = x->right;
    x->right = y->left;
    y->left = x;
    return y;
}
template<typename T>
inline Node<T>* AVLTree<T>::rotationRight(Node<T>* x)
{
    Node<T> *y = x->left;
    x->left = y->right;
    y->right = x;
    return y;
}
template<typename T>
inline Node<T>* AVLTree<T>::successor(Node<T> *node)
{
    while(node->left != nullptr)
        node = node->left;
    return node;
}

template<typename T>
Node<T>* AVLTree<T>::put(Node<T>* &node, const T &key)
{
    if(node == nullptr)
        return new Node<T>(key);
    else if(key < node->key)
        node->left = put(node->left, key);
    else if(key > node->key)
        node->right = put(node->right, key);
    else
        return node;
    int balance = getBalance(node);
    if(balance > 1)
    {
        if(key < node->left->key)
            return rotationRight(node);
        if(key > node->left->key)
        {
            node->left = rotationLeft(node->left);
            return rotationRight(node);
        }
    }
    else if(balance < -1)
    {
        if(key > node->right->key)
            return rotationLeft(node);
        if(key < node->right->key)
        {
            node->right = rotationRight(node->right);
            return rotationLeft(node);
        }
    }
    return node;
}
template<typename T>
inline void AVLTree<T>::put(const T &key)
{
    root = put(root, key);
}
template<typename T>
inline Node<T>* AVLTree<T>::del(Node<T> *node, const T &key)
{
    if(node == nullptr)
        return node;
    if(key < node->key)
        node->left = del(node->left, key);
    else if(key > node->key)
        node->right = del(node->right, key);
    else
    {
        Node<T> *tmp = nullptr;
        if(node->left != nullptr && node->right != nullptr)
        {
            tmp = successor(node->right);
            node->key = tmp->key;
            node->right = del(node->right, tmp->key);
        }
        else if(node->right == nullptr)
        {
            tmp = node;
            node = node->left;
            delete tmp;
        }
        else if(node->left == nullptr)
        {
            tmp = node;
            node = node->right;
            delete tmp;
        }
        else
        {
            delete node;
        }
    }
    int balance = getBalance(node);
    if(balance > 1)
    {
        if(getBalance(node->left) >= 0)
            return rotationRight(node);
        else
        {
            node->left = rotationLeft(node->left);
            return rotationRight(node);
        }
    }
    else if(balance < -1)
    {
        if(getBalance(node->right) <= 0)
            return rotationLeft(node);
        else
        {
            node->right = rotationRight(node->right);
            return rotationLeft(node);
        }
    }
    return node;
}
template<typename T>
inline void AVLTree<T>::del(const T &key)
{
    root = del(root, key);
}
template<typename T>
inline void AVLTree<T>::inOrder(Node<T> *node)
{
    if(node == nullptr)
        return ;
    inOrder(node->left);
    cout << node->key << " ";
    inOrder(node->right);
}
template<typename T>
inline void AVLTree<T>::preOrder(Node<T> *node)
{
    if(node == nullptr)
        return ;
    cout << node->key << " ";
    preOrder(node->left);
    preOrder(node->right);
}
template<typename T>
inline void AVLTree<T>::inOrder()
{
    cout << " in: " ;
    inOrder(root);
    cout << endl;
}
template<typename T>
inline void AVLTree<T>::preOrder()
{
    cout << "pre: ";
    preOrder(root);
    cout << endl;
}
int main()
{
    AVLTree<int> avlT;
    vector<int> vec{1,2,3,4,5,6,7};
    cout << "insert: " << endl;
    for(int i=0;i<int(vec.size());i++)
    {
        avlT.put(vec[i]);
        avlT.inOrder();
        avlT.preOrder();
    }
    cout << "delete: " << endl;
    for(int i=0;i<int(vec.size());i++)
    {
        avlT.del(vec[i]);
        avlT.inOrder();
        avlT.preOrder();
    }
    return 0;
}

测试结果

insert: 
 in: 1 
pre: 1 
 in: 1 2 
pre: 1 2 
 in: 1 2 3 
pre: 2 1 3 
 in: 1 2 3 4 
pre: 2 1 3 4 
 in: 1 2 3 4 5 
pre: 2 1 4 3 5 
 in: 1 2 3 4 5 6 
pre: 4 2 1 3 5 6 
 in: 1 2 3 4 5 6 7 
pre: 4 2 1 3 6 5 7 
delete: 
 in: 2 3 4 5 6 7 
pre: 4 2 3 6 5 7 
 in: 3 4 5 6 7 
pre: 4 3 6 5 7 
 in: 4 5 6 7 
pre: 6 4 5 7 
 in: 5 6 7 
pre: 6 5 7 
 in: 6 7 
pre: 6 7 
 in: 7 
pre: 7 
 in: 
pre: