#include"tnode.h"
typedef struct
{
	TNode *root;
	int size;
}BSTree;
void DeleteTree(TNode *root);
void SetBST(BSTree *T);
void FreeBST(BSTree *T);
int BSTSize(BSTree *T);
TNode *GetRoot(BSTree *T);
int BSTEmpty(BSTree *T);
TNode *BSTLocate(BSTree *T,DataType item);
void BSTInsert(BSTree *T,DataType item);
void BSTDelete(BSTree *T,DataType item);
void clearBST(BSTree *T);
void DeleteTree(TNode *root)
{
	if(root==NULL)
		return;
	if(root->left!=NULL)
		DeleteTree(root->left);
	if(root->right!=NULL)
		DeleteTree(root->right);
	free(root);
}
void SetBST(BSTree *T)
{
	T->root=NULL;
	T->size=0;
}
void FreeBST(BSTree *T)
{
	DeleteTree(T->root);
}
int BSTSize(BSTree *T)
{
	return (T->size);
}
TNode *GetRoot(BSTree *T)
{
	return (T->root);
}
int BSTEmpty(BSTree *T)
{
	if(T->size==0)
		return (1);
	return (0);
}
TNode *BSTLocate(BSTree *T,DataType item)
{
	TNode *t;
	t=T->root;
	while(t!=NULL)
	{
		if(item==t->data)
			break;
		if(item<t->data)
			t=t->left;
		else
			t=t->right;
	}
	return (t);
}
void BSTInsert(BSTree *T,DataType item)
{
	TNode *t,*p,*n;
	n=GetTNode(item,NULL,NULL);
	if(T->size==0)
		{
			T->root=n;
			T->size++;
			return;
		}
		t=T->root;
		p=NULL;
		while(t!=NULL)
		{
			p=t;
			if(item<t->data)
				t=t->left;
			else
				t=t->right;
		}
		if(item<p->data)
			p->left=n;
		else
			p->right=n;
		T->size++;
}
void BSTDelete(BSTree *T,DataType item)
{
	TNode *t,*p,*r,*pr;
	t=T->root;
	p=NULL;
	while(t!=NULL)
		if(item==t->data)
			break;
		else
		{
			p=t;
			if(item<t->data)
				t=t->left;
			else
				t=t->right;
		}
		if(t==NULL)
			return;
		if(t->left==NULL)
		{
			if(p==NULL)
				T->root=t->right;
			else
				p->right=t->right;
			free(t);
		}
		else
		{
			pr=t;
			r=t->left;
			while(r->right!=NULL)
			{
				pr=r;
				r=r->right;
			}
			t->data=r->data;
			if(pr==t)
				pr->left=r->left;
			else
				pr->right=r->left;
			free(r);
		}
		T->size--;
}
void clearBST(BSTree *T)
{
	DeleteTree(T->root);
	T->root=NULL;
	T->size=0;
}