二叉搜索樹的性質：
1.每個節點都有一個作爲搜索依據的關鍵碼(key)，所有節點的關鍵碼都不一樣。
2.左子樹的關鍵碼都小於根節點的關鍵碼
3.右子樹的關鍵碼都大於根節點的關鍵碼
4.左右子樹都是二叉搜索樹
#include<iostream>
using namespace std;
template<class K,class V>
struct BSTreeNode
{
BSTreeNode<K, V>* _left;
BSTreeNode<K, V>* _right;
K _key;
V _value;
BSTreeNode(const K& key, const V& value)
: _left(NULL)
, _right(NULL)
, _key(key)
, _value(value)
{}
};
template < class K, class V>
class BSTree
{
typedef BSTreeNode<K, V> Node;
public:
BSTree()
:_root(NULL)
{}
/*bool Insert(const K& key, const V& value)
{
if (_root == NULL)
{
_root = new Node(key, value);
return true;
}
Node* parent = NULL;
Node* cur = _root;
while (cur)
{
if (cur->_key > key)
{
parent = cur;
cur = cur->_left;
}
else if (cur->_key < key)
{
parent = cur;
cur = cur->_right;
}
else
{
return false;
}
}
if (parent->_key > key)
{
parent->_left = new Node(key, value);
}
else
{
parent->_right = new Node(key, value);
}
return true;
}
Node* Find(const K& key)
{
Node* cur = _root;
while (cur)
{
if (cur->_key > key)
{
cur = cur->_left;
}
else if (cur->_key < key)
{
cur = cur->_right;
}
else
{
return cur;
}
}
return NULL;
}
bool Remove(const K& key)
{
if (_root == NULL)
{
return false;
}
Node* parent = NULL;
Node* cur = _root;
while (cur)
{
if (cur->_key < key)
{
parent = cur;
cur = cur->_right;
}
else if (cur->_key > key)
{
parent = cur;
cur = cur->_left;
}
else
{
if (cur->_left == NULL)//左爲空
{
if (cur == _root)
{
_root = cur->_right;
}
else
{
if (parent->_left == cur)
{
parent->_left = cur->_right;
}
else
{
parent->_right = cur->_right;
}
}
delete cur;
}
else if (cur->_right == NULL)//右爲空
{
if (parent == NULL)
{
_root = cur;
}
else
{
if (parent->_left == cur)
{
parent->_left = cur->_left;
}
else
{
parent->_right = cur->_left;
}
}
delete cur;
}
else//左右都不爲空
{
Node* parent = cur;
Node* left = cur->_right;
while (left->_left)
{
parent = left;
left = left->_left;
}
cur->_key = left->_key;
cur->_value = left->_value;
if (parent->_left == left)
{
parent->_left = left->_right;
}
else
{
parent->_right = left->_right;
}
delete left;
}
return true;
}
}
return false;
}*/
void Inorder()
{
Node* root = _root;
_Inorder(root);
cout << endl;
}
void _Inorder(Node* root)
{
if (root == NULL)
{
return;
}
_Inorder(root->_left);
cout << root->_key << " ";
_Inorder(root->_right);
}
bool InsertR(const K& key, const V& value)
{
return _InsertR(_root, key, value);
}
Node* FindR(const K& key)
{
return _FindR(_root, key);
}
bool RemoveR(const K& key)
{
return _RemoveR(_root, key);
}
protected:
bool _InsertR(Node*& root, const K& key, const V& value)
{
if (root == NULL)
{
root = new Node(key, value);
return true;
}
if (root->_key > key)
{
return _InsertR(root->_left, key, value);
}
else if (root->_key < key)
{
return _InsertR(root->_right, key, value);
}
else
{
return false;
}
}
Node* _FindR(Node* root, const K& key)
{
if (root == NULL)
{
return NULL;
}
if (root->_key == key)
{
return root;
}
if (root->_key > key)
{
return _FindR(root->_left, key);
}
else if (root->_key < key)
{
return _FindR(root->_right, key);
}
}
bool _RemoveR(Node*& root, const K& key)
{
if (root == NULL)
{
return false;
}
if (root->_key > key)
{
return _RemoveR(root->_left, key);
}
else if (root->_key < key)
{
return _RemoveR(root->_right, key);
}
else
{
Node* del = root;
if (root->_left == NULL)//左爲空
{
root = root->_right;//這裏不用考慮被刪結點的父節點，因爲遞歸使用的引用，傳過來的參數其實是父親結點的左孩子或者右孩子
}
else if (root->_right == NULL)//右爲空
{
root = root->_left;
}
else//左右都不爲空
{
Node* parent = root;
Node* left = root->_right;
while (left->_left)
{
parent = left;
left = left->_left;
}
del = left;
root->_key = left->_key;
root->_value = left->_value;
if (parent->_left == left)
{
parent->_left = left->_right;
}
else
{
parent->_right = left->_right;
}
}
delete del;
}
return true;
}
protected:
Node* _root;
};