package dasherJava.core.collections;

import java.util.ArrayList;
import java.util.Collections;

public class DynamicPriorityQueue<E extends Comparable<E>> extends ArrayList<E> {
	
	//A simple priority queue implementation that finds the minimum (or maximum if invert is true)
	//by iterating over all elements. This is not very efficient, but is required to handle
	//dynamically and frequently changing priorities.
	//Implementation note: Is extending ArrayList the best option, or are there more efficient ones?
	
	private final boolean invert;
	
	public DynamicPriorityQueue(boolean invert) {
		this.invert=invert;
	}
	
	public E peek() { //Returns the head of the queue without removing it
		return invert ? Collections.max(this) : Collections.min(this);
	}
	
	public E poll() { //Removes and returns the head of the queue
		E head = invert ? Collections.max(this) : Collections.min(this);
		remove(head);
		return head;
	}
	
	public void addAll(E[] elements) {
		for (E e : elements) {
			add(e);
		}
	}
	
	public void removeAll(E[] elements) {
		for (E e : elements) {
			remove(e);
		}
	}
}