A Simple Online Competitive Adaptation of Lempel-Ziv Compression with Efficient Random Access Support
Author(s)Dutta, Akashnil; Levi, Reut; Ron, Dana; Rubinfeld, Ronitt
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We present a simple adaptation of the Lempel Ziv 78' (LZ78) compression scheme that supports efficient random access to the input string. The compression algorithm is given as input a parameter ε > 0, and with very high probability increases the length of the compressed string by at most a factor of (1 + ε). The access time is O(log n + 1/ε[superscript 2]) in expectation, and O(log n/ε[superscript 2]) with high probability. The scheme relies on sparse transitive-closure spanners. Any (consecutive) substring of the input string can be retrieved at an additional additive cost in the running time of the length of the substring. The main benefit of the proposed scheme is that it preserves the online nature and simplicity of LZ78, and that for every input string, the length of the compressed string is only a small factor larger than that obtained by running LZ78.
DepartmentMassachusetts Institute of Technology. Computer Science and Artificial Intelligence Laboratory; Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
2013 Data Compression Conference (DCC)
Institute of Electrical and Electronics Engineers (IEEE)
Dutta, Akashnil, Reut Levi, Dana Ron, and Ronitt Rubinfeld. “A Simple Online Competitive Adaptation of Lempel-Ziv Compression with Efficient Random Access Support.” 2013 Data Compression Conference (20-22 March 2013). Snowbird, UT, USA. IEEE, p.113-122.
Author's final manuscript
INSPEC Accession Number: 13596910