The actual Set interface in the java.util package has several methods that are beyond those implemented by our search tree in this chapter. Write a version of SearchTree that adds some or all of these methods. The methods to add are the following (some headers are slightly modified; see the Java API Specification for descriptions of each method):

• public void addAll(SearchTree tree)
• public void clear()
• public boolean containsAll(SearchTree tree)
• public boolean equals(Object o)
• public boolean isEmpty()
• public boolean remove(Object o)
• public void removeAll(SearchTree tree)
• public void retainAll(SearchTree tree)
• public Object[] toArray()