Fenwick trees are a O(log N) data structure for updating cumulative sums. This implementation comes with an operation to find a least element for which real-valued cumulative sum reaches certain value, and allows for storage of arbitrary information in the nodes.
Official releases are on Hackage.
This package is also a part of Stackage - a stable subset of Hackage.
0.1.2.1 Dec 2014
* GHC 7.10 release