public static Node GetByIndex(BaseRedBlackTree <Node> tree, int index, GetCount getCount)
{
if (index < 0 || index >= tree.Count)
{
throw new ArgumentException($"Index out of range {index} [0-{tree.Count})");
}
Node node = tree.Root;
while (true)
{
if (node.Left != null && index < getCount(node.Left))
{
node = node.Left;
continue;
}
if (node.Right == null)
{
return(node);
}
index -= getCount(node) - getCount(node.Right);
if (index < 0)
{
return(node);
}
node = node.Right;
}
}
public static int IndexOf(BaseRedBlackTree <Node> tree, Node node, GetCount getCount)
{
if (node == null)
{
return(-1);
}
Debug.Assert(node.Root == node);
int index = node.Left != null?getCount(node.Left) : 0;
while (node.Parent != null)
{
if (node.Side) //if we're on the right side of a parent, add all the left sum
{
index += getCount(node.Parent) - getCount(node);
}
node = node.Parent;
}
return(index);
}