,
Masayuki Takeda
Creative Commons Attribution 3.0 Unported license
A square is a non-empty string of form YY. The longest common square subsequence (LCSqS) problem is to compute a longest square occurring as a subsequence in two given strings A and B. We show that the problem can easily be solved in O(n^6) time or O(|M|n^4) time with O(n^4) space, where n is the length of the strings and M is the set of matching points between A and B. Then, we show that the problem can also be solved in O(sigma |M|^3 + n) time and O(|M|^2 + n) space, or in O(|M|^3 log^2 n log log n + n) time with O(|M|^3 + n) space, where sigma is the number of distinct characters occurring in A and B. We also study lower bounds for the LCSqS problem for two or more strings.
@InProceedings{inoue_et_al:LIPIcs.CPM.2018.15,
author = {Inoue, Takafumi and Inenaga, Shunsuke and Hyyr\"{o}, Heikki and Bannai, Hideo and Takeda, Masayuki},
title = {{Computing longest common square subsequences}},
booktitle = {29th Annual Symposium on Combinatorial Pattern Matching (CPM 2018)},
pages = {15:1--15:13},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-074-3},
ISSN = {1868-8969},
year = {2018},
volume = {105},
editor = {Navarro, Gonzalo and Sankoff, David and Zhu, Binhai},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.CPM.2018.15},
URN = {urn:nbn:de:0030-drops-86946},
doi = {10.4230/LIPIcs.CPM.2018.15},
annote = {Keywords: squares, subsequences, matching rectangles, dynamic programming}
}