二叉搜索树

#include <iostream>
#include <stack>
using namespace std;

typedef int ElemType;

typedef struct TreeNode *BinTree;
typedef BinTree Position;
typedef struct TreeNode       //二叉树的表示
{
	ElemType Data;
	BinTree Left;
	BinTree Right;
};


//在二叉搜索树中查找值为X的结点
//递归算法
Position Find(ElemType X, BinTree BST)
{
	if (!BST) return NULL;
	if (X > BST->Data)
		return Find(X, BST->Right);
	else if (X < BST->Data)
		return Find(X, BST->Left);
	else
		return BST;
}

//非递归算法
Position Find(ElemType X, BinTree BST)
{
	while (BST)
	{
		if (X < BST->Data)   
			BST = BST->Left;
		else if (X > BST->Data)
			BST = BST->Right;
		else
			return BST;
	}
	return NULL;//查找失败
}

//在二叉搜索树中查找值最大和最小的元素
Position FindMin(BinTree BST)
{
	if (!BST)
		return NULL; //空的二叉搜素树返回NULL
	else if (!BST->Left)
		return BST;  //找到最左叶结点并返回
	else
		FindMin(BST->Left);
}

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

//二叉搜索树的插入
BinTree Insert(ElemType X, BinTree BST)
{
	if (!BST) //若原树为空，生成并返回一个结点的二叉搜索树
	{
		BST = new struct TreeNode;
		BST->Data = X;
		BST->Left = BST->Right = NULL;
	}
	else if (X < BST->Data)
		BST->Left = Insert(X, BST->Left);  //递归插入左子树
	else if (X > BST->Data)
		BST->Right = Insert(X, BST->Right); //递归插入右子树
	//else X已经存在，什么都不做
	return BST;
}

//二叉搜索树的删除
BinTree Delete(ElemType X, BinTree BST)
{
	if (!BST)
		cout << "要删除的元素未找到";
	else if (X < BST->Data)
		BST->Left = Delete(X, BST->Left);
	else if (X > BST->Data)
		BST->Right = Delete(X, BST->Right);
	else //找到了要删除的结点
	{
		if (BST->Left && BST->Right) //被删除的结点有左右两个子结点
		{
			BinTree Tmp = FindMin(BST->Right); //在右子树中找最小的元素填充删除结点
			BST->Data = Tmp->Data;
			BST->Right = Delete(BST->Data, BST->Right);
		}
		else   //被删除的结点有一个或无子结点
		{
			if (!BST->Left)
				BST = BST->Right;
			else if (!BST->Right)
				BST = BST->Left;
			delete BST;
		}
	}
	return BST;
}