PTA 6-12 (二叉树的递归删除)

BinTree Insert( BinTree BST, ElementType X )
{
    if (BST==NULL) {
        BinTree tmp=(BinTree)malloc(sizeof(struct TNode));
        tmp->Data=X;
        tmp->Left=tmp->Right=NULL;
        return tmp;
    };
    if (X<BST->Data)  
        BST->Left=Insert(BST->Left,X);
    else              
        BST->Right=Insert(BST->Right,X);
    return BST;
}

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

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

BinTree Delete( BinTree BST, ElementType X ) {
    BinTree TMP;
    if (BST==NULL) {
        printf ("Not Found
");
        return NULL;
    }
    if (X<BST->Data) 
        BST->Left=Delete (BST->Left,X);
    else  if (X>BST->Data)           
        BST->Right=Delete (BST->Right,X);
    else {
        if (BST->Left!=NULL&&BST->Right!=NULL)  {
            TMP=FindMin (BST->Right);
            BST->Data=TMP->Data;
            BST->Right=Delete (BST->Right,TMP->Data);
        }
        else {
            TMP=BST;
            if (BST->Left!=NULL) 
                BST=BST->Left;
            else if (BST->Right!=NULL)
                BST=BST->Right;
            else BST=NULL;
        }
    }
    return BST;
}