As the code above reveals, insertion into a BST always occurs at a previously null link.

Deletion from a BST is more complicated. For example, what should happen if the data at the root is deleted?

Deletion is handled by considering three essential cases:

1. The BST is empty. 
        - Easy. Do nothing.

2. The data in Node t to be deleted has a null child (so 1 or 0 children)
        - Make the parent of t point to t's other child

3. The data in Node t to be deleted has two children. 
        - Find t's successor Node s (use private s min(t.right) )
        - Delete Node s from the subtree t.right (s has at most one child)
        - Replace t with s by setting s.right to the modified right
          subtree of t and setting s.left to t's left subtree.