title: Second max in BST
body: <p>This is an interview question. Find the second max in BST.</p>
  
  <p>The max element is the rightmost leaf in the BST. The second max is either its parent or its left child. So the solution is to traverse the BST to find the rightmost leaf and check its parent and left child.</p>
  
  <p>Does it make sense? </p>