二叉搜尋樹的各種操作！

程式碼：

#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 ); /* 先序遍歷，由裁判實現，細節不表 */
void InorderTraversal( BinTree BT );  /* 中序遍歷，由裁判實現，細節不表 */

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;
}

void PreorderTraversal( BinTree BT ){ /* 先序遍歷，由裁判實現，細節不表 */
	printf(" %d",BT->Data);
	if(BT->Left) PreorderTraversal(BT->Left);
	if(BT->Right) PreorderTraversal(BT->Right);
}
	
void InorderTraversal( BinTree BT ){  /* 中序遍歷，由裁判實現，細節不表 */
	if(BT->Left) PreorderTraversal(BT->Left);
	printf(" %d",BT->Data);
	if(BT->Right) PreorderTraversal(BT->Right);
	
}
BinTree Insert( BinTree BST, ElementType X ){//插入 
	if(!BST){//到達插入點，即葉子節點的左或右 
		BST = (BinTree)malloc(sizeof(struct TNode));
		BST->Data = X;
		BST->Left = NULL;
		BST->Right = NULL;
	}
	else if(X < BST->Data)
		BST->Left = Insert(BST->Left,X);
	else if(X > BST->Data)
		BST->Right = Insert(BST->Right,X);
	return BST;
}
BinTree Delete( BinTree BST, ElementType X ){
	BinTree Tmp;
	if(!BST) printf("Not Found\n");
	else if(X < BST->Data) BST->Left = Delete(BST->Left,X);
	else if(X > BST->Data) BST->Right = Delete(BST->Right,X);
	else//找到刪除的元素 
		if(BST->Left && BST->Right){//左右子樹都有結點
			Tmp = FindMin(BST->Right);//在右子樹上找最小結點
			BST->Data = Tmp->Data;//將最小結點賦值到刪除元素位置上 
			BST->Right = Delete(BST->Right,BST->Data);//將剛剛找到的最小結點刪除 
		}
		else{
			Tmp = BST;
			if(!BST->Left)//當沒有左子樹時將右樹鏈到刪除位置上 
				BST = BST->Right;
			else if(!BST->Right)//當沒有右子樹時將左樹鏈到刪除位置上
				BST = BST->Left;
			free(Tmp);//釋放刪除結點空間 
		}
	return BST;//返回結點 
} 
 
Position Find( BinTree BST, ElementType X ){
	if(!BST) return NULL;
	if(BST->Data == X) return BST;
	if(X < BST->Data) return Find(BST->Left,X);
	else return Find(BST->Right,X);
}
Position FindMin( BinTree BST ){
	if(!BST) return NULL;//空樹
	if(!BST->Left) return BST;//找到最左邊值並返回 
	return FindMin(BST->Left); //繼續向左尋找 
} 
Position FindMax( BinTree BST ){
	/*if(!BST) return NULL;//空樹
	if(!BST->Right) return BST;//找到
	return FindMax(BST->Right); */
	if(BST)
		while(BST->Right) BST = BST->Right;
	return BST;
}