1 //与上一次实现不同，这里使用了大量的指针引用，
  2 //因此节省了一个指向父节点的指针
  3 #include<iostream>
  4 #include<vector>
  5 #include<ctime>
  6 #include<cstdlib>
  7 #include<sstream>
  8 using namespace std;
  9 
 10 template<class T>
 11 class BinarySearchTree
 12 {
 13     private:
 14         struct Node
 15         {
 16             T data;
 17             Node *left;
 18             Node *right;
 19             int deep;
 20             Node(T val,int deep)
 21             {
 22                 data = val;
 23                 deep = deep;
 24                 left = NULL;
 25                 right = NULL;
 26             }
 27 
 28             private:
 29             Node() 
 30             {
 31             }
 32         };
 33         Node *root;
 34         int size;
 35 
 36     public:
 37         BinarySearchTree()
 38         {
 39             root = NULL;
 40             size = 0;
 41         }
 42         ~BinarySearchTree()
 43         {
 44             clear(root);
 45             root = NULL;
 46             size = 0;
 47         }
 48         Node*& findMin(Node *&node) const
 49         {
 50             if(node->left == NULL)
 51                 return node;
 52             else
 53                 return findMin(node->left);
 54         }
 55 
 56         void  insert(Node *&node,T val,int deep )
 57         {
 58             if(size == 0)
 59             {
 60                 root = new Node(val,0);
 61                 size++;
 62                 return;
 63             }
 64             if(node == NULL)
 65             {
 66                 node = new Node(val,deep);
 67                 size++;
 68                 return;
 69             }
 70             if(val > node->data)
 71                 insert(node->right,val,node->deep+1);
 72             else if(val < node->data)
 73                 insert(node->left,val,node->deep+1);
 74             else if(val == node->data)
 75             {
 76             }
 77         }
 78 
 79         bool contain(Node *& node,T val) const
 80         {
 81             if(node == NULL)
 82                 return false;
 83 
 84             if(val > node->data)
 85                 return contain(node->right,val);
 86             else if(val < node->data)
 87                 return contain(node->left,val);
 88             else
 89                 return true;
 90         }
 91 
 92         void remove(Node* &node,T val)
 93         {
 94             if(node == NULL)
 95             {
 96                 cout<<"remove() error!\n";
 97                 return;
 98             }
 99             if(val > node->data)
100                 remove(node->right,val);
101             else if(val < node->data)
102                 remove(node->left,val);
103             else if(val == node->data)
104             {
105                 if(node->left == NULL && node->right == NULL)
106                 {
107                     delete node;
108                     node = NULL;
109                     size--;
110                 }
111                 else if(node->left == NULL && node->right != NULL)
112                 {
113                     Node *p = node;
114                     node = node->right;
115                     delete p;
116                     size--;
117                 }
118                 else if(node->left != NULL && node->right == NULL)
119                 {
120                     Node *p = node;
121                     node = node->left;
122                     delete p;
123                     size--;
124                 }
125                 else if(node->left != NULL && node->right != NULL)
126                 {
127                     Node* &p = findMin(node->right);
128                        node->data = p->data;
129                     Node *tmp = p;
130                     p = p->right;
131                     delete tmp;
132                     size--;    
133                 }
134             }
135         }
136         void clear(Node* &node)
137         {
138             if(node->left != NULL)
139                 clear(node->left);
140             if(node->right != NULL)
141                 clear(node->right);
142 
143             delete node;
144             node = NULL;
145         }
146         void print(Node *node)
147         {
148             if(node == NULL)
149                 return;
150             cout<<node->data<< " ";
151             if(node->left != NULL)
152                 print(node->left);
153             if(node->right != NULL)
154                 print(node->right);
155         }
156         void insert(T val)
157         {
158             insert(root,val,0);
159         }
160         void remove(T val)
161         {
162             remove(root,val);
163         }
164         void print()
165         {
166             print(root);
167             cout<<"\n";
168         }
169 };
170 
171 int main()
172 {
173     BinarySearchTree<int> tree;
174 
175     srand((unsigned int)time(0));
176     for(int i=0;i<20;i++)
177         tree.insert(rand()%100-50);
178     tree.print();
179     return 0;
180 }