I was contacted by a recruiter, and we had an informal chat about LinkedIn and what I am looking for. He was very relaxed and explained things in detail. I just had my first interview and am waiting for feedback. Hopefully, I will have tons of interviews.

public interface PointsOnAPlane {

/**
 * Stores a given point in an internal data structure
 */
void addPoint(Point point);

/**
 * For a given 'center' point, returns a subset of 'm' stored points that are
 * closer to the center than others.
 * 
 * E.g. Stored: (0, 1) (0, 2) (0, 3) (0, 4) (0, 5)
 * 
 * findNearest(new Point(0, 0), 3) -> (0, 1), (0, 2), (0, 3)
 */
Collection<Point> findNearest(Point center, int m);

}

The interviewer was very helpful. I realised the importance of thinking aloud.