public static void MainTest(string[] args)
{
TextInput StdIn = new TextInput();
int N = StdIn.ReadInt();
Point2D[] points = new Point2D[N];
for (int i = 0; i < N; i++)
{
int x = StdIn.ReadInt();
int y = StdIn.ReadInt();
points[i] = new Point2D(x, y);
}
GrahamScan graham = new GrahamScan(points);
foreach (Point2D p in graham.Hull())
{
Console.WriteLine(p);
}
}
/// <summary>
/// Computes the farthest pair of points in the specified array of points.</summary>
/// <param name="points">the array of points</param>
/// <exception cref="NullReferenceException">if <c>points</c> is <c>null</c> or if any
/// entry in <c>points[]</c> is <c>null</c></exception>
///
public FarthestPair(Point2D[] points)
{
GrahamScan graham = new GrahamScan(points);
// single point
if (points.Length <= 1)
{
return;
}
// number of points on the hull
int M = 0;
foreach (Point2D p in graham.Hull())
{
M++;
}
// the hull, in counterclockwise order
Point2D[] hull = new Point2D[M + 1];
int m = 1;
foreach (Point2D p in graham.Hull())
{
hull[m++] = p;
}
// all points are equal
if (M == 1)
{
return;
}
// points are collinear
if (M == 2)
{
best1 = hull[1];
best2 = hull[2];
bestDistanceSquared = best1.DistanceSquaredTo(best2);
return;
}
// k = farthest vertex from edge from hull[1] to hull[M]
int k = 2;
while (Point2D.Area2(hull[M], hull[k + 1], hull[1]) > Point2D.Area2(hull[M], hull[k], hull[1]))
{
k++;
if (k == hull.Length - 1)
{
break;
}
}
int j = k;
for (int i = 1; i <= k; i++)
{
//Console.WriteLine(hull[i] + " and " + hull[j] + " are antipodal");
if (hull[i].DistanceSquaredTo(hull[j]) > bestDistanceSquared)
{
best1 = hull[i];
best2 = hull[j];
bestDistanceSquared = hull[i].DistanceSquaredTo(hull[j]);
}
while ((j < M) && Point2D.Area2(hull[i], hull[j + 1], hull[i + 1]) > Point2D.Area2(hull[i], hull[j], hull[i + 1]))
{
j++;
//Console.WriteLine(hull[i] + " and " + hull[j] + " are antipodal");
double distanceSquared = hull[i].DistanceSquaredTo(hull[j]);
if (distanceSquared > bestDistanceSquared)
{
best1 = hull[i];
best2 = hull[j];
bestDistanceSquared = hull[i].DistanceSquaredTo(hull[j]);
}
}
}
}