Grammar compressed sequences with rank/select support

Sequence representations supporting not only direct access to their symbols, but also rank/select operations, are a fundamental building block in many compressed data structures. Several recent applications need to represent highly repetitive sequences, and classical statistical compression proves ineffective. We introduce, instead, grammar-based representations for repetitive sequences, which use up to 6% of the space needed by statistically compressed representations, and support direct access and rank/select operations within tens of microseconds. We demonstrate the impact of our structures in text indexing applications. (C) 2016 Elsevier B.V. All rights reserved.European Union, 690941 / FONDECYT, Chile, 1-140796 / CDTI EXP, 000645663/ITC-20133062 / Xunta de Galicia (PGE), GRC2013/053 / Xunta de Galicia (FEDER), GRC2013/053 / MICINN (PGE), TIN2009-14560-C03-02, TIN2010-21246-C02-01, TIN2013-46238-C4-3-R, TIN2013-47090-C3-3-P, AP2010-6038 / MICINN (FEDER), TIN2009-14560-C03-02, TIN2010-21246-C02-01, TIN2013-46238-C4-3-R, TIN2013-47090-C3-3-P, AP2010-603