Internal Quasiperiod Queries

07/27/2020

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by   Maxime Crochemore, et al.

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Internal pattern matching requires one to answer queries about factors of a given string. Many results are known on answering internal period queries, asking for the periods of a given factor. In this paper we investigate (for the first time) internal queries asking for covers (also known as quasiperiods) of a given factor. We propose a data structure that answers such queries in O(log n loglog n) time for the shortest cover and in O(log n (loglog n)^2) time for a representation of all the covers, after O(n log n) time and space preprocessing.