internal virtual Tree GetParent(Tree node) { if (node is IHasParent) { return(node.Parent()); } if (nodesToParents == null) { nodesToParents = new IdentityHashMap <Tree, Tree>(); } if (nodesToParents.IsEmpty()) { FillNodesToParents(root, null); } return(nodesToParents[node]); }
/// <summary>Returns <code>true</code> if this set contains no elements.</summary> /// <returns><code>true</code> if this set contains no elements.</returns> public override bool IsEmpty() { return(map.IsEmpty()); }