private static void pushSubHullDown(RedBlackNode current, bool isLeftHalf)
{
if (current != null && !current.IsLeaf && current.GetConvexHull(isLeftHalf) != null)
{
Treap <Point> leftHalf;
Treap <Point> rightHalf;
Treap <Point> .SplitBySize(current.GetConvexHull(isLeftHalf), current.GeLowerSubHullSize(isLeftHalf), out leftHalf, out rightHalf);
current.Left.SetConvexHull(isLeftHalf, Treap <Point> .Merge(leftHalf, current.Left.GetConvexHull(isLeftHalf)));
current.Right.SetConvexHull(isLeftHalf, Treap <Point> .Merge(current.Right.GetConvexHull(isLeftHalf), rightHalf));
current.SetConvexHull(isLeftHalf, null);
}
}