typedef struct TreeNode *Position;

typedef struct TreeNode *SearchTree;

struct TreeNode{

    ElementType X;

    SearchTree Left;

    SearchTree Right;

};

//建立一颗空树的例程

SearchTree

MakeEmpty( SearchTree T )

{

    if( T != NULL )

    {//先做空儿子，在弄父亲

        MakeEmpty(T->Left);

        MakeEmpty(T->Right);

        free(T);

    }

    return NULL;//避免返回值的警告

}

//二叉查找树的Find操作（尾递归）

SearchTree

Find( SearchTree T, ElementType X )

{

    if( T == NULL )

        return NULL;

    if( T->Element > X )

        return Find( T->Left, X );

    else if( T->Element < X )

        return Find( T->Right, X );

    else

        return T;

}

//对二叉查找树FindMin操作(非递归实现，自创)

SearchTree

FindMin( SearchTree T )

{

    SearchTree Tmp;

    if(T == NULL )

        return NULL;//空树

    Tmp = T->Left;

    while( Tmp != NULL )

    {

        T = Tmp;

        Tmp = Tmp->Left;

    }

    return T->Element;

}

//FindMin操作非递归实现正解

SearchTree

FindMin( SearchTree T )

{

    if(T != NULL )

    {

        while( T->Left != NULL )

            T = T->Left;

    }

    return T;

}

//FindMin递归正解

SearchTree

FindMin( SearchTree T )

{

    if( T == NULL )

        return NULL;

    if( T->Left != NULL ){

        T = T->Left;

        return FindMin( T );

    }

    else

        return T;

}

//FindMax非递归

SearchTree

FindMax( SearchTree T )

{

    if( T == NULL )

        return NULL;

    while( T->Right != NULL )

    {

        T = T->Right;

    }

    return T;

}

//FindMax递归

SearchTree

FindMax( SearchTree T )

{

    if( T == NULL )

        return NULL;

    if( T->Right != NULL ){

        T = T->Right;

        return FindMax( T );

    }

    return T;

}

//FindMax递归超正解

SearchTree

FindMax( SearchTree T )

{

    if( T == NULL )

        return NULL;

    else

    if( T->Right == NULL )

        return T;

    else

        return FindMax( T->Right );

}