04-树7 二叉搜索树的操作集 (30 分)

04-树7 二叉搜索树的操作集 (30 分)

本题要求实现给定二叉搜索树的5种常用操作。

函数接口定义：

BinTree Insert( BinTree BST, ElementType X );
BinTree Delete( BinTree BST, ElementType X );
Position Find( BinTree BST, ElementType X );
Position FindMin( BinTree BST );
Position FindMax( BinTree BST );

其中BinTree结构定义如下：

typedef struct TNode *Position;
typedef Position BinTree;
struct TNode{
ElementType Data;
BinTree Left;
BinTree Right;
};
函数Insert将X插入二叉搜索树BST并返回结果树的根结点指针；
函数Delete将X从二叉搜索树BST中删除，并返回结果树的根结点指针；如果X不在树中，则打印一行Not Found并返回原树的根结点指针；
函数Find在二叉搜索树BST中找到X，返回该结点的指针；如果找不到则返回空指针；
函数FindMin返回二叉搜索树BST中最小元结点的指针；
函数FindMax返回二叉搜索树BST中最大元结点的指针。

裁判测试程序样例：

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

typedef int ElementType;
typedef struct TNode *Position;
typedef Position BinTree;
struct TNode{
    ElementType Data;
    BinTree Left;
    BinTree Right;
};

void PreorderTraversal( BinTree BT ); /* 先序遍历，由裁判实现，细节不表 */
void InorderTraversal( BinTree BT );  /* 中序遍历，由裁判实现，细节不表 */

BinTree Insert( BinTree BST, ElementType X );
BinTree Delete( BinTree BST, ElementType X );
Position Find( BinTree BST, ElementType X );
Position FindMin( BinTree BST );
Position FindMax( BinTree BST );

int main()
{
    BinTree BST, MinP, MaxP, Tmp;
    ElementType X;
    int N, i;

    BST = NULL;
    scanf("%d", &N);
    for ( i=0; i<N; i++ ) {
        scanf("%d", &X);
        BST = Insert(BST, X);
    }
    printf("Preorder:"); PreorderTraversal(BST); printf("\n");
    MinP = FindMin(BST);
    MaxP = FindMax(BST);
    scanf("%d", &N);
    for( i=0; i<N; i++ ) {
        scanf("%d", &X);
        Tmp = Find(BST, X);
        if (Tmp == NULL) printf("%d is not found\n", X);
        else {
            printf("%d is found\n", Tmp->Data);
            if (Tmp==MinP) printf("%d is the smallest key\n", Tmp->Data);
            if (Tmp==MaxP) printf("%d is the largest key\n", Tmp->Data);
        }
    }
    scanf("%d", &N);
    for( i=0; i<N; i++ ) {
        scanf("%d", &X);
        BST = Delete(BST, X);
    }
    printf("Inorder:"); InorderTraversal(BST); printf("\n");

    return 0;
}
/* 你的代码将被嵌在这里 */

输入样例：

10
5 8 6 2 4 1 0 10 9 7
5
6 3 10 0 5
5
5 7 0 10 3

输出样例：

Preorder: 5 2 1 0 4 8 6 7 10 9
6 is found
3 is not found
10 is found
10 is the largest key
0 is found
0 is the smallest key
5 is found
Not Found
Inorder: 1 2 4 6 8 9

Notes

1. 当删除节点左右孩子都不空时，找到左子树的最大节点（可以不用循环）
2. 对递归的出口不是很清晰，diyibianbug出耗费了很长时间 若递归出不加return，那只有第一层可以正常返回，第二层顺序执行完便强制返回0.
3. left！= null && right == null – right == null && left != null …

code

BinTree Delete( BinTree BST, ElementType X ){
	if(BST == NULL){   printf("Not Found\n"); return BST;}
    else if(BST->Data == X){
        if(BST->Left != NULL && BST->Right != NULL){
            BinTree p = FindMax(BST->Left);
			//while(p->Right) p = p->Right;
			p->Right = BST->Right;
            p = BST->Left;
            free(BST);
            return p; 
        }
        else if(BST->Left != NULL && BST->Right == NULL){
            BinTree p = BST->Left;
            free(BST);
            return p;
        }
        else if(BST->Right != NULL && BST->Left == NULL){
            BinTree p = BST->Right;
            free(BST);
            return p;
        }
		else if((BST->Left != NULL) && (BST->Right == NULL)){
			BinTree p = BST;
			free(p);
			return NULL;
		}
    }
    else if(X < BST->Data) {
        BST->Left = Delete(BST->Left, X);
		return BST;
    }
	else if(X > BST->Data){ BST->Right = Delete(BST->Right, X); return BST;}
}

BinTree Insert( BinTree BST, ElementType X ) {
    if(BST == NULL){
        BST = (BinTree)malloc(sizeof(Position));
        BST->Data = X;
        BST->Left = NULL;
        BST->Right = NULL;
  
    }
	else if(X > BST->Data)  BST->Right =Insert(BST->Right, X);
    else if(X < BST->Data)  BST->Left = Insert(BST->Left, X);
	return BST;
}//diyidabug
 
Position Find( BinTree BST, ElementType X ){
    if(BST == NULL) return 0;
    else if(BST->Data == X) return BST;
    else if(X < BST->Data) Find(BST->Left, X);
    else Find(BST->Right, X);
}

Position FindMin( BinTree BST ){
    if(!BST) return BST;
    if(BST->Left == NULL) return BST;
    else FindMin(BST->Left);
}

Position FindMax( BinTree BST ){
    if(!BST) return BST;
    if(BST->Right == NULL) return BST;
    else FindMax(BST->Right);
}

完全实现

#include<iostream>
#include<cstdio>
#include<stack>
using namespace std;
typedef int ElementType;
typedef struct TNode *Position;
typedef Position BinTree;
struct TNode{
    ElementType Data;
    BinTree Left;
    BinTree Right;
};

void PreorderTraversal( BinTree BT ); /* 先序遍历，由裁判实现，细节不表 */
void InorderTraversal( BinTree BT );  /* 中序遍历，由裁判实现，细节不表 */

BinTree Insert( BinTree BST, ElementType X );
BinTree Delete( BinTree BST, ElementType X );
Position Find( BinTree BST, ElementType X );
Position FindMin( BinTree BST );
Position FindMax( BinTree BST );

int main()
{
    BinTree BST, MinP, MaxP, Tmp;
    ElementType X;
    int N, i;

    BST = NULL;
    scanf("%d", &N);
    for ( i=0; i<N; i++ ) {
        scanf("%d", &X);
        BST = Insert(BST, X);
    }
    printf("Preorder:"); PreorderTraversal(BST); printf("\n");
    MinP = FindMin(BST);
    MaxP = FindMax(BST);
    scanf("%d", &N);
    for( i=0; i<N; i++ ) {
        scanf("%d", &X);
        Tmp = Find(BST, X);
        if (Tmp == NULL) printf("%d is not found\n", X);
        else {
            printf("%d is found\n", Tmp->Data);
            if (Tmp==MinP) printf("%d is the smallest key\n", Tmp->Data);
            if (Tmp==MaxP) printf("%d is the largest key\n", Tmp->Data);
        }
    }
    scanf("%d", &N);
    for( i=0; i<N; i++ ) {
        scanf("%d", &X);
        BST = Delete(BST, X);
    }
    printf("Inorder:"); InorderTraversal(BST); printf("\n");

    return 0;
}


BinTree Delete( BinTree BST, ElementType X ){
	if(BST == NULL){   printf("Not Found\n"); return BST;}
    else if(BST->Data == X){
        if(BST->Left != NULL && BST->Right != NULL){
            BinTree p = BST->Left;
			while(p->Right) p = p->Right;
			p->Right = BST->Right;
            p = BST->Left;
            //free(BST);
            return p; 
        }
        else if(BST->Left != NULL && BST->Right == NULL){
            BinTree p = BST->Left;
            //free(BST);
            return p;
        }
        else if(BST->Right  != NULL && BST->Left == NULL){
            BinTree p = BST->Right;
            //free(BST);
            return p;
        }
		else{
			BinTree p = BST;
			//free(p);
			return NULL;
		}
    }
    else if(X < BST->Data) {
        BST->Left = Delete(BST->Left, X);
		return BST;
    }
	else{ BST->Right = Delete(BST->Right, X); return BST;}
}

BinTree Insert( BinTree BST, ElementType X ) {
    if(BST == NULL){
        BST = (BinTree)malloc(sizeof(Position));
        BST->Data = X;
        BST->Left = NULL;
        BST->Right = NULL;
  
    }
	else if(X > BST->Data)  BST->Right =Insert(BST->Right, X);
    else if(X < BST->Data)  BST->Left = Insert(BST->Left, X);
	return BST;
}//diyidabug
 
Position Find( BinTree BST, ElementType X ){
    if(BST == NULL) return 0;
    else if(BST->Data == X) return BST;
    else if(X < BST->Data) Find(BST->Left, X);
    else Find(BST->Right, X);
}

Position FindMin( BinTree BST ){
    if(BST->Left == NULL) return BST;
    else FindMin(BST->Left);
}

Position FindMax( BinTree BST ){
    if(BST->Right == NULL) return BST;
    else FindMax(BST->Right);
}
void InorderTraversal( BinTree BT ){
    stack<BinTree> s;
    s.push(BT);
    while(s.size() > 0){
        BinTree temp = s.top();
        while(temp) {temp = temp->Left; s.push(temp);}
        s.pop();
        if(s.size() > 0){
			temp = s.top();
		    s.pop();
            cout  <<  temp->Data << " ";
            s.push(temp->Right);
        }
    }
}
void PreorderTraversal( BinTree BT ){
    stack<BinTree> s;
    s.push(BT);
    while(s.size() > 0){
        BinTree temp = s.top();
        while(temp) {   cout <<( temp->Data)<< " ";  temp = temp->Left;  s.push(temp);}
        s.pop();
  
        if(s.size() > 0){
			temp = s.top();
			s.pop();
            s.push(temp->Right);
        }
    }
}