public class HullAlgorithm {

  static double distance (Pointd p, Pointd q)
  {
    return Math.sqrt ( (p.x-q.x)*(p.x-q.x) + (p.y-q.y)*(p.y-q.y) );
  }

  public double findLargest (Pointd[] points)
  {
    // For each pair of points: compute the distance, recording
    // the largest such distance:
    double maxDistance = 0;
    for (int i=0; i<points.length-1; i++) {
      for (int j=1; j<points.length; j++) {
        double dist = distance (points[i], points[j]);
        if (dist > maxDistance)
          maxDistance = dist;
      }
    }
    return maxDistance;
  }

  public double findLargestDistance (Pointd[] points)
  {
    // 1. Find the convex hull:
    Hull hull = new Hull (points);
    // 2. Extract the points:
    Pointd[] hullPoints = hull.getPoints();
    // 3. Compute an all-pairs largest-distance:
    return findLargest (hullPoints);
  }

}