PointSET.java

public class PointSET {

    private SET<Point2D> set;

    // construct an empty set of points
    public PointSET() { set = new SET<Point2D>(); }

    // is the set empty?
    public boolean isEmpty() { return set.isEmpty(); }

    // number of points in the set
    public int size() { return set.size(); }

    // add the point p to the set (if it is not already in the set)
    // proportional to logarithm of N in the worst case
    public void insert(Point2D p) { set.add(p); }

    // does the set contain the point p?
    // proportional to logarithm of N in the worst case
    public boolean contains(Point2D p) { return set.contains(p); }

    // draw all of the points to standard draw
    public void draw() {
         StdDraw.setPenColor(StdDraw.BLACK);
         StdDraw.setPenRadius(.01);

         for (Point2D p : set)
             StdDraw.point(p.x(), p.y());

         StdDraw.show(0);
    }

    // all points in the set that are inside the rectangle
    // proportional to N in the worst case
    public Iterable<Point2D> range(RectHV rect) {
        Stack<Point2D> s = new Stack<Point2D>();

        for (Point2D p : set)
            if (rect.contains(p))
                s.push(p);

        return s;
    }

    // a nearest neighbor in the set to p: null if set is empty
    // proportional to N
    public Point2D nearest(Point2D p) {
        if (isEmpty()) return null;

        double dis, minDis = Double.MAX_VALUE;
        Point2D q = null;

        for (Point2D ip : set) {
            dis = p.distanceSquaredTo(ip);
            if (dis < minDis) {
                minDis = dis;
                q = ip;
            }
        }

        return q;
    }
}