The BST class represents an ordered symbol table of generic key-value pairs. It supports the usual Put, Get, Indexer, Contains, Delete, Count, and IsEmpty methods. It also provides ordered methods for finding the Minimum, Maximum, Floor, and Ceiling. It also provides a Keys method for iterating over all of the keys. A symbol table implements the Associative array abstraction: when associating a value with a key that is already in the symbol table, the convention is to replace the old value with the new value. Unlike DictionaryTKey, TValue, this class uses the convention that values cannot be null. Setting the value associated with a key to null is equivalent to deleting the key from the symbol table.

This implementation uses a left-leaning red-black BST. It requires that the key type implements the Comparable interface and calls the compareTo() and method to compare two keys. It does not call either equals() or GetHashCode(). The Put, Contains, Remove, Minimum, Maximum, Ceiling, and Floor operations each take logarithmic time in the worst case, if the tree becomes unbalanced. The Count, and IsEmpty operations take constant time. Construction takes constant time.