As an important optimization a bottom out technique is used to compactify the tree to the level of nodes, where bit operations become possible. As a side effect, the optimization now relies on the underlying architecture. This leads to the fact, that the maximum of elements which can be stored is 2^16 on a 32-bit architecture and 2^32 on a 64-bit architecture. This was intentionally chosen for two reasons: i) to keep the size of a single node also depending from the underlying architecture. ii) for bitoperations, which the tree is relying on, to use the native word size of the architecture without emulating bigger entities.