/**
* Internal method to insert into a subtree.
*
* @param x the item to insert.
* @param t the node that roots the tree.
* @return the new root.
* @throws DuplicateItemException if x is already present.
*/
protected BinaryNode<AnyType> insert(AnyType x, BinaryNode<AnyType> t) {
if (t == null) t = new BinaryNode<AnyType>(x);
else if (x.compareTo(t.element) < 0) t.left = insert(x, t.left);
else if (x.compareTo(t.element) > 0) t.right = insert(x, t.right);
else throw new DuplicateItemException(x.toString()); // Duplicate
return t;
}
/**
* Internal method to remove from a subtree.
*
* @param x the item to remove.
* @param t the node that roots the tree.
* @return the new root.
* @throws ItemNotFoundException if x is not found.
*/
protected BinaryNode<AnyType> remove(AnyType x, BinaryNode<AnyType> t) {
if (t == null) throw new ItemNotFoundException(x.toString());
if (x.compareTo(t.element) < 0) t.left = remove(x, t.left);
else if (x.compareTo(t.element) > 0) t.right = remove(x, t.right);
else if (t.left != null && t.right != null) // Two children
{
t.element = findMin(t.right).element;
t.right = removeMin(t.right);
} else t = (t.left != null) ? t.left : t.right;
return t;
}
