CareerCup Convert a BST to max heap without using extra memory and in as optimum time as possible

Convert a BST to max heap without using extra memory and in as optimum time as possible

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/* Bottom Up recursive code. 
* Basic Idea: Swap the right child to its parent bottom up to make it a Max Heap. 
*/ 

NODE* BSTMaxHeapify(NODE* Tree) 
{ 
if(Tree==NULL) 
return Tree; 
BSTMaxHeapify(Tree->left); 
BSTMaxHeapify(Tree->right); 
return(BSTMaxHeapSwap(Tree,Tree->right)); 
} 

NODE* BSTMaxHeapSwap(NODE* Root, NODE* RootRight) 
{ 
if(RootRight==NULL) 
return Root; 
else 
Swap the Root and RootRight Node; 
return RootRight; 
} 

Plz comment if I have made any mistake