// A nearest neighbor to point p; null if the symbol table is empty.
    public Point2D nearest(Point2D p) {
        if (bst.isEmpty()) { return null; }

        double min = Double.POSITIVE_INFINITY;

        Point2D minPoint = new Point2D(0.0, 0.0);

        Queue<Point2D> q = new Queue<Point2D>();

        for (Point2D point: bst.keys()) {
            if (point.equals(p)) { continue; }


            double distance = point.distanceSquaredTo(p);

            if (distance < min) {
                min = distance;
                minPoint = point;
            }
        }

        return minPoint;
    }