public T KeyByIndex(int index)
{
RBOrderedTreeNode <T> node = GetByOrder(index);
if (node != null)
{
return(node.Key);
}
return(default(T));
}
///<summary>
///Get order index of item
///This operation is O(logN) operation
///</summary>
public int GetOrder(RBOrderedTreeNode <T> aItem)
{
RBTreeNodeBase <T, RBOrderedNodeParam> node = aItem;
int idx = node.mParam.mRank;
while (true)
{
if (node.mParent == null)
{
break;
}
if (node.mParent.mRight == node)
{
idx += node.mParent.mParam.mRank;
}
node = node.mParent;
}
return(idx - 1);
}
