package jutil;

/**
 * A queue sorted by priority. Possible implementations include
 * sorted list, binary heap, leftist heap, skew heap, etc.
 */
public interface PriorityQueue extends java.io.Serializable {
	/**
	 * Removes and returns the highest priority element.
	 * @return highest priority element.
	 * @throws EmptyQueueException if the queue is empty.
	 */
   Comparable deleteMin() throws EmptyQueueException;
   /**
    * Inserts an element according to its priority. Elements
    * are assumed to be Comparables compared by priority, where the
    * smaller element has the higher priority.
    * @param x   the element to be inserted.
    * @throws OverflowException if the queue is full.
    */
   void insert(Comparable x) throws OverflowException;
   /**
    * @return size == 0.
    */
   boolean isEmpty();
   /**
    * @return the number of elements in the queue.
    */
   int size();
   /**
    * Removes all elements from the queue.
    */
   void clear();
}