This can be used effectively to avoid the need to generate and compute support for all combinations in the input data. However, the approach requires: 1) a number of passes of the data set and 2) the construction of candidate sets to be counted in the next pass.
The implementation of this structure can be optimized by storing levels in the tree in the form of arrays, thus reducing the number of links needed and providing direct indexing. For the latter purpose, it is more convenient to build a “reverse” version of the tree, refered to as a T-tree (Total support tree).