/** The Dictionary abstract class */
public interface Dictionary<Key, E> {

  /** Reinitialize dictionary */
  public void clear();

  /** Insert a record.
   * @param k The key for the record being inserted.
   * @param e The record being inserted. */
  public void insert(Key k, E e);

  /** Remove and return a record.
   * @param k The key of the record to be removed.
   * @return A matching record. If multiple records match "k", remove an arbitrary one. Return null if no record with key "k" exists. */
  public E remove(Key k);

  /** Remove and return arbitrary record from dictionary.
   * @return the record removed, or null if none exists. */
  public E removeAny();

  /** @return A record matching "k" (null if none exists).
   * If multiple records match, return an arbitrary one. 
   * @param k The key of the record to find */
  public E find(Key k);

  /** @return The number of records in the dictionary. */
  public int size();
};