#include <stdio.h>
#include <stdlib.h>
#include <iostream>
using namespace std;
typedef struct node 
{ 
	int key; 
	
	struct node *LChild,*RChild,*Parent; 
}BSTNode,*BSTree; 


void CreatBST(BSTree *bst);
BSTree SearchBST(BSTree bst,int key) ;
void InsertBST(BSTree *bst,int key) ;
void InsertBST2(BSTree *bst,int key) ;
BSTNode * DelBST(BSTree t,int k) ;
BSTNode * DelBST2(BSTree t,BSTNode *z) ;//主函数如何调用？
BSTNode * TreeSuccessor(BSTNode *x);//寻找后继 主函数如何调用？

void print_bst(BSTree t) {
	if (t!=NULL)
	{
		print_bst(t->LChild);
		printf(" %d ", t->key);
		print_bst(t->RChild);
	}
}

const int n = 10;

/*Creat new tree*/ 
void CreatBST(BSTree *bst) 
{ 
	int i; 
	int key; 
	*bst=NULL; 
	cout<<"请输入n（n=10）个数："<<endl;
	scanf("%d",&key);
	InsertBST2(bst,key); 

	for(i=2;i <=n;i++) 
	{ 
		scanf("%d",&key); 
		InsertBST2(bst,key); 
	} 
	cout<<"创建成功！"<<endl;
	//return bst; 
} 


/*Search*/ //递归版本
BSTree SearchBST(BSTree bst,int key) 
{ 
	if(bst==NULL) {
	    cout<<"cannot find it"<<endl;
		return NULL; 
	}
	else 
		if(bst->key==key) 
		{
			cout<<"find it:\t"<<bst->key<<endl;	
			return bst;
		}
		else 
			if(key <bst->key) 
				return SearchBST(bst->LChild, key); 
			else 
				return SearchBST(bst->RChild, key); 
} 

/*Search*/ //非递归版本
BSTree SearchBST2(BSTree bst,int key) {
	while(bst!=NULL&&bst->key!=key){
		if(key<bst->key)
			bst=bst->LChild;
		else
			bst=bst->RChild;
	}
	return bst;
}

/*Insert*/ //递归版本
void InsertBST(BSTree *bst,int key) 
{ 
	BSTree t; 
	if(*bst==NULL) 
	{ 
		t=(BSTree)malloc(sizeof(BSTNode)); 
		t->key=key; 
		t->LChild=NULL; 
		t->RChild=NULL; 
		//t->Parent=NULL;
		*bst=t; 
	} 
	else 
		if(key <(*bst)->key) {
			InsertBST(&((*bst)->LChild),key); 
			//(*bst)->LChild->Parent=*bst;
		}
		else 
			if(key>(*bst)->key){ 
				InsertBST(&(*bst)->RChild,key); 
				//(*bst)->RChild=*bst;
			}
} 
//insert 非递归版本

 void InsertBST2(BSTree *bst,int key) {
	  BSTNode *y=NULL;
	  BSTNode *x=*bst;
	  BSTree t; 
	
		t=(BSTree)malloc(sizeof(BSTNode)); 
		t->key=key; 
		t->LChild=NULL; 
		t->RChild=NULL; 
		t->Parent=NULL;
	  while(x!=NULL){
		  y=x;//y指向x的前驱
		  if(key<x->key)
			  x=x->LChild;
		  else
			  x=x->RChild;
	  }
	  t->Parent=y;
	  //永远不执行,与上面的if重复
	  if(y==NULL)
		  *bst=t; 
	  else 
		  if(key<y->key)
		     y->LChild=t;
	     else
		    y->RChild=t;
	//}

  }

/*Delet*/ //递归版本
BSTNode * DelBST(BSTree t,int k) 
{ 
	BSTNode *p,*f,*s,*q; 
	p=t; 
	f=NULL; 
	while(p) 
	{ 
		if(p->key==k) 
			break; 
		f=p; 
		if(p->key>k) 
			p=p->LChild; 
		else 
			p=p->RChild; 
	} 
	if(p==NULL) 
		return t; 
	if(p->LChild==NULL) 
	{ 
		if(f==NULL) 
			t=p->RChild; 
		else 
			if(f->LChild==p) 
				f->LChild=p->RChild; 
			else 
				f->RChild=p->LChild; 
		free(p); 
	} 
	else 
	{ 
		q=p; 
		s=s->LChild; 
		while(s->RChild) 
		{ 
			q=s; 
			s=s->RChild; 
		} 
		if(q==p) 
			q->LChild=s->LChild; 
		else 
			q->RChild=s->LChild; 
		p->key=s->key; 
		free(s); 
	} 
	return t; 
} 

/*Delet*/ //非递归版本
BSTNode * DelBST2(BSTree t,BSTNode *z) {
	BSTNode *x=NULL;//x被置为y的非NULL子女，若y无子女时，x被置为NULL
	BSTNode *y=NULL;//y或者是输入结点z(若z至多只有1个子女)，或者是z的后继（若z有2个子女）
	if(z->LChild==NULL||z->RChild==NULL)//z至多有一个子女
		y=z;
	else
		y=TreeSuccessor(z);//z有2个子女

	if(y->LChild!=NULL)
		x=y->LChild;
	else
		x=y->RChild;
	if(x!=NULL)
		x->Parent=y->Parent;
	if(y->Parent==NULL)
		t=x;
	else if(y==y->Parent->LChild)
		y->Parent->LChild=x;
	else
		y->Parent->RChild=x;
	if(y!=z)
		z->key=y->key;
	return y;
}

//return 一个指向以结点t为根的子树中最小元素的指针
BSTNode * TreeMin(BSTree t){
	while(t->LChild!=NULL)
		t=t->LChild;
	return t;
}

//return 一个指向以结点t为根的子树中最大元素的指针
BSTNode * TreeMax(BSTree t){
	while(t->RChild!=NULL)
		t=t->RChild;
	return t;
}

BSTNode * TreeSuccessor(BSTNode *x){//寻找后继,返回指向后继的指针
	if(x->RChild!=NULL)
		return TreeMin(x->RChild);
	BSTNode *y=x->Parent;
	while(y!=NULL&&x==y->RChild){
		x=y;
		y=y->Parent;
	}
	return y;
}
/*Main*/ // 0 1 3 2 6 4 5 9 7 8
int main() 
{ 
	BSTNode * root; //定义指向任意结点的
	BSTree  temp;//一般用来定义头指针变量
	//BSTNode * temp;
	int loop,i,data; 
	loop=true; 
	while(loop) 
	{ 
		printf("\n\n\n"); 
		printf(" 1.Creat\n"); 
		printf(" 2.Search\n"); 
		printf(" 3.Insert\n"); 
		printf(" 4.Delete\n"); 
		printf(" 5.Print\n"); 
		printf(" 6.Min\n"); 
		printf(" 7.Max\n"); 
		printf(" 0.exit  main\n"); 
		scanf("%d",&i); 
		switch(i) 
		{ 
		case 0: {
			loop=false;
			break;
				}
		case 1: 
			{ 
				CreatBST(&root);
				
			}break; 
		case 2: 
			{ 
				printf("Please input the data you want search.\n"); 
				scanf("%d",&data); 
				temp=SearchBST2(root,data);
				if(temp!=NULL){
					cout<<"find it:"<<temp->key<<endl;	
				}
				else
					cout<<"cannot find it"<<endl;

			}break; 
		case 3: 
			{ 
				printf("Please input the data you want insert.\n"); 
				scanf("%d",&data); 
				InsertBST(&root,data);
			}break; 
		case 4: 
			{ 
				printf("Please input the data you want delete.\n"); 
				scanf("%d",&data); 
				root=DelBST(root,data); 
			}break; 
		case 5:{
			printf("\n"); 
			if (root!=NULL) 
				printf("The BSTree's root is:%d\n",root->key); 
			print_bst(root);
			break; 

			   } 
			   case 6:{
			   temp=TreeMin(root);
			   cout<<"最小值："<<temp->key<<endl;
			   break; 

			   } 
			    case 7:{
			   temp=TreeMax(root);
			   cout<<"最大值："<<temp->key<<endl;
			   break; 

			   } 
			   
		} 
	} 
}