二叉搜索树的基本操作-04-树7 二叉搜索树的操作集 (30分)

#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;

//freopen("treeTest.txt","r",stdin);

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;
}

void PreorderTraversal( BinTree BST )
{
if(BST == NULL) return;
printf(" %d ",BST->Data);
PreorderTraversal(BST->Left);
PreorderTraversal(BST->Right);
}

void InorderTraversal( BinTree BST )
{
if(BST == NULL) return;
InorderTraversal(BST->Left);
printf(" %d ",BST->Data);
InorderTraversal(BST->Right);
}

/* 你的代码将被嵌在这里 */
BinTree Insert( BinTree BST, ElementType X )
{
if(BST == NULL){
BinTree tmp = (BinTree)malloc(sizeof(struct TNode));
tmp->Data = X;
tmp->Left = NULL;
tmp->Right = NULL;
BST = tmp;
}else if(BST->Data > X){
BST->Left = Insert(BST->Left, X);
}else{
BST->Right = Insert(BST->Right, X);
}

return BST;
}

//删除结点的代码是难点，需要重点掌握
BinTree Delete( BinTree BST, ElementType X )
{
BinTree tmp;
if(BST == NULL){
printf("Not Found\n");
//return NULL;
}else if(BST->Data > X){
BST->Left = Delete(BST->Left, X);
}else if(BST->Data < X){
BST->Right = Delete(BST->Right, X);
}else{  //找到了
if(BST->Left && BST->Right){    //被删除的结点有两个子结点
tmp = FindMin(BST->Right);  //找到右子树中的最小值来替换
BST->Data = tmp->Data;
BST->Right = Delete(BST->Right, tmp->Data);
}else{          //被删除的结点有一个或0个子结点
tmp = BST;
if( !BST->Left ){
BST = BST->Right;
} else if(!BST->Right){
BST = BST->Left;
}
free(tmp);//一定要记得free，否则造成内存泄漏！
}

}
return BST;
}

Position Find( BinTree BST, ElementType X )
{
if(BST == NULL) return NULL;
if(BST->Data == X){
return BST;
}else if(BST->Data > X){
return Find(BST->Left, X);
}else{
return Find(BST->Right, X);
}
}

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

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