Prague Stringology Conference 2018

Akihiro Nishi, Yuto Nakashima, Shunsuke Inenaga, Hideo Bannai and Masayuki Takeda

O(n log n)-time Text Compression by LZ-style Longest First Substitution

Mauer et al. (A Lempel-Ziv-style Compression Method for Repetitive Texts, PSC 2017) proposed a hybrid text compression method called LZ-LFS which has both features of Lempel-Ziv 77 factorization and longest first substitution. They showed that LZ-LFS can achieve better compression ratio for repetitive texts, compared to some state-of-the-art compression algorithms. The drawback of Mauer et al.'s method is that their LZ-LFS compression algorithm takes O(n2) time on an input string of length n. In this paper, we show a faster LZ-LFS compression algorithm that works in O(n log n) time. We also propose a simpler version of LZ-LFS that can be computed in O(n) time.

Download paper: Article in PostScript Article in PDF BibTeX Reference
 PostScript   PDF   BibTeX reference