TY - GEN
T1 - On two LZ78-style grammars
T2 - 24th International Symposium on String Processing and Information Retrieval, SPIRE 2017
AU - Badkobeh, Golnaz
AU - Gagie, Travis
AU - Inenaga, Shunsuke
AU - Kociumaka, Tomasz
AU - Kosolobov, Dmitry
AU - Puglisi, Simon J.
N1 - Publisher Copyright:
© Springer International Publishing AG 2017.
PY - 2017
Y1 - 2017
N2 - We investigate two closely related LZ78-based compression schemes: LZMW (an old scheme by Miller and Wegman) and LZD (a recent variant by Goto et al.). Both LZD and LZMW naturally produce a grammar for a string of length n; we show that the size of this grammar can be larger than the size of the smallest grammar by a factor Ω(n1/3) but is always within a factor (Formula presented). In addition, we show that the standard algorithms using Θ(z) working space to construct the LZD and LZMW parsings, where z is the size of the parsing, work in Ω(n5/4) time in the worst case. We then describe a new Las Vegas LZD/LZMW parsing algorithm that uses O(z log n) space and O(n + zlog2n) time w.h.p.
AB - We investigate two closely related LZ78-based compression schemes: LZMW (an old scheme by Miller and Wegman) and LZD (a recent variant by Goto et al.). Both LZD and LZMW naturally produce a grammar for a string of length n; we show that the size of this grammar can be larger than the size of the smallest grammar by a factor Ω(n1/3) but is always within a factor (Formula presented). In addition, we show that the standard algorithms using Θ(z) working space to construct the LZD and LZMW parsings, where z is the size of the parsing, work in Ω(n5/4) time in the worst case. We then describe a new Las Vegas LZD/LZMW parsing algorithm that uses O(z log n) space and O(n + zlog2n) time w.h.p.
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U2 - 10.1007/978-3-319-67428-5_5
DO - 10.1007/978-3-319-67428-5_5
M3 - Conference contribution
AN - SCOPUS:85030148563
SN - 9783319674278
T3 - Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
SP - 51
EP - 67
BT - String Processing and Information Retrieval - 24th International Symposium, SPIRE 2017, Proceedings
A2 - Venturini, Rossano
A2 - Fici, Gabriele
A2 - Sciortino, Marinella
PB - Springer Verlag
Y2 - 26 September 2017 through 29 September 2017
ER -