二叉搜索树

来源：互联网发布：e博乐网络编辑：程序博客网时间：2024/06/05 21:49
二叉搜索树是这样定义的：
左子树如果有，key值都比根节点的key值小，
右子树如果有，key值都比根节点的key值大，
左子树和右子树都是二叉搜索树；
模拟实现一个模板类BSTree.hpp实现搜索二叉树的一些基本功能
#pragma once#include<iostream>template<class K>struct BSTreeNode{    BSTreeNode(const K& key) :_key(key), _left(NULL), _right(NULL){}    K _key;    BSTreeNode* _left;    BSTreeNode* _right;};template<class K>class BSTree{    typedef BSTreeNode<K> Node;public:    BSTree() :_root(NULL){}    BSTree(const BSTree & t)    {        _copy(t._root);    }    void InOrder()    {        _InOrder(_root);        std::cout << std::endl;    }    bool InsertR(const K& key)//递归    {        return _InsertR(_root, key);    }    bool Insert(const K& key)    {        if (_root == NULL)        {            _root = new Node(key);        }        else        {            Node* parent = NULL;            Node* root = _root;            while (root)            {                parent = root;                if (key > root->_key)                    root = root->_right;                else if (key < root->_key)                    root = root->_left;                else                    return false;            }            if (key < parent->_key)                parent->_left = new Node(key);            else                 parent->_right = new Node(key);        }        return true;    }    bool RemoveR(const K& key)//递归    {        return _RemoveR(_root, key);    }    bool Remove(const K& key)    {        Node* parent = _root;        Node* root = _root;        while (root)        {            if (key > root->_key)            {                parent = root;                root = root->_right;            }            else if (key < root->_key)            {                parent = root;                root = root->_left;            }            else            {                break;            }        }//找到要删除的位置        Node* del = root;        if (root == NULL)            return false;//没找到位置        if (root->_left == NULL)        {            if (root == _root)                _root = _root->_right;            else            {                if (root == parent->_right)                    parent->_right = root->_right;//要删除的点左边没东西，让父节点指向它的右节点即可；                else                    parent->_left = root->_left;            }        }        else if (root->_right == NULL)        {            if (root == _root)                _root = _root->_left;            else            {                if (root == parent->_right)                    parent->_right = root->_right;                else                    parent->_left = root->_left;            }        }        else        {            Node* rootL = root->_left;            parent = root;            while (rootL->_right)//左右两边都有节点，找左边最大的节点            {                parent = rootL;                rootL = rootL->_right;            }            root->_key = rootL->_key;            del = rootL;            if (root == parent->_right)                parent->_right = rootL->_left;            else                parent->_left = rootL->_left;        }        delete del;        del = NULL;        return true;    }    Node* FindR(const K& key)    {        return _FindR(_root, key);    }    Node* Find(const K& key)    {        Node* root = _root;        while (root)        {            if (key > root->_key)                root = root->_right;            else if (key < root->_key)                root = root->_left;            else                return root;        }        return root;    }    ~BSTree()    {        _delete(_root);    }private:    Node* _FindR(Node* root, const K& key)    {        if (root == NULL)            return NULL;        if (key > root->_key)            return _FindR(root->_right, key);        else if (key < root->_key)            return _FindR(root->_left, key);        else            return root;    }    bool _RemoveR(Node* &root, const K& key)    {        if (root == NULL)            return false;        if (key > root->_key)            return _RemoveR(root->_right, key);        else if (key < root->_key)            return _RemoveR(root->_left, key);        else        {            Node* del = root;            if (root->_left == NULL)            {                root = root->_right;            }            else if (root->_right == NULL)            {                root = root->_left;            }            else            {                Node* parent = root;                Node* left = root->_left;                while (left->_right)                {                    parent = left;                    left = left->_right;                }                del = left;                root->_key = left->_key;                if (left == parent->_right)                    parent->_right = left->_left;                else                    parent->_left = left->_left;            }            delete del;        }        return true;    }    bool _InsertR(Node*& root, const K& key)    {        if (root == NULL)            root = new Node(key);        if (key > root->_key)            return _InsertR(root->_right, key);        else if (key < root->_key)            return _InsertR(root->_left, key);        else            return false;    }    void _InOrder(Node* root)    {        if (root)        {            _InOrder(root->_left);            std::cout << root->_key << " ";            _InOrder(root->_right);        }    }    void _copy(Node* root)    {        if (root == NULL)            return;        Node *_root = new Node(root->_key);        _root->_left = NULL;        _root->_right = NULL;        if (root->_left)            _copy(root->_left);        if (root->_right)            _copy(root->_right);    }    void _delete(Node*& root)    {        if (root != NULL)        {            _delete(root->_left);            _delete(root->_right);            delete root;            root = NULL;        }    }protected:    Node* _root;};
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