Distribution-Aware Compressed Full-Text Indexes

In this paper we address the problem of building a compressed self-index that, given a distribution for the pattern queries and a bound on the space occupancy, minimizes the expected query-time within that index-space bound. We solve this problem by exploiting a reduction to the problem of finding a minimum weight K-link path in a particular Directed Acyclic Graph. Interestingly enough, our solution is independent of the underlying compressed index in use. Our experiments compare this optimal strategy with several other standard approaches, showing its effectiveness in practice.