/*  Generic interface for a Priority Queue.  Each inserted object has a
    "priority" which is determined by the .compareTo function.  If 
    a.compareTo(b)>0 then a has higher priority than b.
*/

public interface PriorityQ<T>
{
    int size();       // number of values currently in queue
    boolean add(T x); // insert new value into queue, returns true if x!=null
    T poll();   // returns and deletes the value with the highest priority.
                // returns null if queue is empty
    T peek();   // returns the value with highest priority, without delete,
                // returns null if queue is empty
    boolean contains(T x); //if x is contained in queue using .equals()
    boolean remove(T x);   // removes a single instance of x from queue
                           // returns false if nothing was removed
    
}//interface PriorityQ
// March 2021