/**
 * Implements PriorityQueue2 using an unsorted ArrayList
 */
import java.util.*;

public class PQ2ArrayList<T> {
    private ArrayList<T> list;
    private Comparator<T> c;
    
    public PQ2ArrayList(Comparator<T> c) {
        this.list = new ArrayList<T>();
        this.c = c;
    }

	/**
	 * Returns the number of items in the queue.
	 */
	public int size() {
	    return this.list.size();
	}
	
	/**
	 * Adds a new item to the priority queue.
	 * @param item the item to add
	 */
	public void add(T item) {
	    this.list.add( item );
    }                
	
	/**
	 * Removes the item with highest priority from the queue.
	 * @return
	 */
	public T remove() {
	    if (size() == 0)
	        return null;
	    T biggestSoFar = list.get(0);
	    for (T item: list) {
	        if (c.compare( biggestSoFar, item ) < 0) {
                biggestSoFar = item;
            }                
        }
        this.list.remove( biggestSoFar );
        return biggestSoFar;
	}
	
	public static void main( String[] args ) {
	    
        PQ2ArrayList<Integer> pq = new PQ2ArrayList<Integer>(new IntComparator());
        pq.add( 5 );
        pq.add( 10 );
        pq.add( 1 );
        System.out.println( "removing " + pq.remove() );
        System.out.println( "size is now " + pq.size() );
	}
}

// for testing purposes!!!
class IntComparator implements Comparator<Integer> {
    public IntComparator() {;}
    
    public int compare(Integer o1, Integer o2) {
        return o1-o2;
    }
    
}