查找和二叉排序树变双向链表备忘

//查找 
#include<stdio.h>
#include<stdlib.h>

//定义一个待查找顺序表
#define MAXSIZE 20	// 顺序表最大长度
typedef int KeyType; //定义关键字类型
typedef struct{
	KeyType key; //关键字项
	char otherinfo; //其他数据项这里用char举例 
}ElemType;
typedef struct{ //顺序表结构类型定义 
	ElemType *r; // r[0] 不用或用作哨兵 
	int length; //表长 
}SS,*SSTable; //Sequential Search Table
//SSTable ST; //定义顺序表ST
//顺序查找 
int Search_Seq0(SSTable ST,KeyType key){
	ST->r[0].key=key; //哨兵 
	for(int i=1;i<=ST->length;i++){
		if(ST->r[i].key==key){
			return i;
		}
	}
	return 0;
}
int Search_Seq(SSTable ST,KeyType key){
	ST->r[0].key=key;
	int i;
	for(i=ST->length;ST->r[i].key!=key;i--);
	return i;
}
//折半查找:有序表才能折半查找！ 
int Search_Bin(SSTable ST,KeyType key){
	int low=1,high=ST->length;
	while(low<=high){
	int mid=(low+high)/2;
	if(key==ST->r[mid].key) return mid;
	else if(key>ST->r[mid].key){
		low=mid+1;
	}
	else high=mid-1;//key<mid到前半段找 
	}
	return 0;//查找失败 
}
//递归Recursion折半查找
int SearchBinRecursion(SSTable ST,int key,int low,int high){
	if(low>high) return 0; //找不到
	int mid=(low+high)/2;
	if(key==ST->r[mid].key) return mid;
	else if(key>ST->r[mid].key) 
	return SearchBinRecursion(ST,key,(mid+1),high);
	else SearchBinRecursion(ST,key,low,(mid-1));
}

//二叉排序链表建立
//typedef struct{
//	KeyType key;
//	char otherinfo;
//}ElemType; 
typedef struct BSTNode{
	ElemType data;
	struct BSTNode *lch,*rch;
}BSTNode,*BSTree;
//二叉链表录入
BSTree CreateBSTree(){
	BSTree T;
	ElemType tree;
	scanf("%d-",
	if(tree.key!=0){ //0代表空位 
		T=(BSTree)malloc(sizeof(BSTNode));
		T->data=tree;
		T->lch=CreateBSTree();
		T->rch=CreateBSTree();
	}
	else T=NULL;
	return T;
}

//二叉排序树的插入
BSTree InsertBST(BSTree T,int key){
	ElemType e;
	e.key=key;
	e.otherinfo='f';
	if(!T){//如果T为NULL 
		BSTree S=(BSTree)malloc(sizeof(BSTNode));
		S->data=e;
		S->lch=S->rch=NULL;//把新结点*S作为叶子结点 
		T=S; //把新结点*S链接到插入位置T 
	}
	else if(e.key<T->data.key) //如果key<当前值插入左子树
	T->lch=InsertBST(T->lch,key);
	else if(e.key>T->data.key) //key>当前值则插入右子树
	T->rch=InsertBST(T->rch,key);
	return T; 
}
//二叉树建立
int a[9]={5,3,2,1,4,7,6,8,-1};
int i=0;
 BSTree CreatBST(){
 	BSTree T=NULL;
 	int key;
 	key=a[i++]; //scanf("%d,",
 	while(key!=-1){ //-1作为结束符 
	 	T=InsertBST(T,key);
	 	key=a[i++];//scanf("%d,",
	 }
	 return T;
 }

//二叉排序链表的查找 返回key结点 
BSTree SearchBSTree(BSTree S,int key){
	if((!S)||key==S->data.key) return S;
	else if(key>S->data.key) S=SearchBSTree(S->rch,key);
	else S=SearchBSTree(S->lch,key);
	return S;
}
//删除结点函数 
 BSTree deleteNode(BSTree T){
 	BSTree p;
 	if(T->lch==NULL&=NULL){ //叶子结点 
	 	p=T;
		T=NULL;
		free(p);
		return T;
	 }
	 else if(T->rch==NULL){ //右子树为空 
	 	p=T;
	 	T=T->lch;
	 	free(p);
	 	return T;
	 }
	 else if(T->lch==NULL){ //左子树为空 
	 	p=T;
	 	T=T->rch;
	 	free(p);
	 	return T;
	 }
	 else{ //左右子树都不为空 
	 	//拿左子树上最大值替换T 
	 	BSTree parent=T;
	 	BSTree pre=T->lch;
	 	//左子树最右支就是左子树最大数
		while(pre->rch){
			parent=pre; //parent保存pre上一个结点 
			pre=pre->rch;
		} 
		T->data=pre->data; //pre是左支最大值替换T
		if(parent!=T){ //如果T有右子树则上while执行parent不等于T 
			parent->rch=pre->lch; //则把pre左子树接到上级右子树 
		}
		else{	//T	无右支while(pre->rch)未执行 
			T->lch=pre->lch; //则把左支接上去 
		}
		free(pre);
		return T;
	 }
 }
 
 //二叉排序树的删除
  BSTree DeleteBST(BSTree T,int key){
  	//找到这个结点位置
  	if(!T) return T;
  	else{
 	 	if(T->data.key==key)
 	 	T=deleteNode(T);
 	 	else if(key>T->data.key)
 	 	T->rch=DeleteBST(T->rch,key);
 	 	else T->lch=DeleteBST(T->lch,key);
 	 	return T;
 	 }
  }
 
 //二叉树中序遍历
 int InOrder(BSTree T){
 	if(!T) return 0;
 	else{
	 	InOrder(T->lch);
	 	printf("%d ",T->data.key);
	 	InOrder(T->rch);
	 }
 } 

//把二叉树变为双向链表
BSTree pre=NULL;
BSTree Change(BSTree T){//LBR中序线索化 
	BSTree p=T;
	if(!p) return NULL;
	else{
		p->lch= Change(p->lch);
		if(!p->lch){
			p->lch=pre;
		}
		if(pre&&!pre->rch){
			pre->rch=p;
		}
		pre=p;
		p->rch=Change(T->rch);
	}
	return p;
}
BSTree ChangeB(BSTree T){ 
	T=Change(T);
	/*根应该指向左子树的右子树或右子树的左子树*/
	BSTree p=T; pre=NULL;
	while(p->lch){
		pre=p; p=p->lch;
		if(p->rch!=pre && pre->lch!=p->rch){
			pre->lch=p->rch;
		}
	}
	pre=NULL;p=T;
	while(p->rch){
		pre=p;p=p->rch;
		if(p->lch!=pre && pre->rch!=p->lch){
			pre->rch=p->lch; 
		}
	}
	while(p->lch){
		p=p->lch;
	}//找到链表头节点返回
	return p; 
}

int main(){
	//SS SS;
//	SSTable ST=(SSTable)malloc(sizeof(SS));
//	ST->r=(ElemType*)malloc(21*sizeof(ElemType));
//	ST->length=20;
//	for(int i=1;i<=20;i++){
//		ST->r[i].key=i;
//		ST->r[i].otherinfo='z';
//	}
//	int a=Search_Seq(ST,3);
//	int b=Search_Seq0(ST,17);
//	int c=Search_Bin(ST,1);
//	int d=SearchBinRecursion(ST,7,1,20);
//	printf("%d %d %d %d\n",a,b,c,d);
	//BSTree T=CreateBSTree();
	BSTree T=CreatBST();
	BSTree S=SearchBSTree(T,6);
	printf("%d %p %p\n",S->data.key,S->lch,S->rch);
	InOrder(T);printf("\n");
//	T=DeleteBST(T,4);
//	InOrder(T);printf("\n");
	T=ChangeB(T);
	while(T){
		printf("%d ",T->data.key);
		T=T->rch;
	}
	return 0;
}