// Copyright 2003, Trustees of Indiana University
// Please see the license in the file ../LICENSE

import java.util.ArrayList;

public class mutable_queue<
	      Vertex,
	      Compare extends StrictWeakOrdering<Vertex>>
    implements MutableQueue<Vertex> {

  private ArrayList<Vertex> vertices_;
  private Compare compare_;

  public void push(Vertex v) {
    vertices_.add(v);
  }

  public Vertex pop() {
    if (empty()) return null;
    Vertex best = vertices_.get(0);
    int best_idx = 0;
    for (int i = 1; i < vertices_.size(); ++i)
      if (compare_.less(vertices_.get(i), best)) {
	best = vertices_.get(i);
	best_idx = i;
      }
    vertices_.remove(best_idx);
    return best;
  }

  public boolean empty() {
    return vertices_.isEmpty();
  }

  public void update(Vertex v) {}

  public mutable_queue(Compare compare) {
    compare_ = compare;
    vertices_ = new ArrayList<Vertex>();
  }
}