,
Maxime Crochemore
,
Costas S. Iliopoulos,
Tomasz Kociumaka
,
Solon P. Pissis
,
Jakub Radoszewski
,
Wojciech Rytter,
Tomasz Walen
Creative Commons Attribution 3.0 Unported license
In the Longest Common Factor with k Mismatches (LCF_k) problem, we are given two strings X and Y of total length n, and we are asked to find a pair of maximal-length factors, one of X and the other of Y, such that their Hamming distance is at most k. Thankachan et al. [Thankachan et al. 2016] show that this problem can be solved in O(n log^k n) time and O(n) space for constant k. We consider the LCF_k(l) problem in which we assume that the sought factors have length at least l. We use difference covers to reduce the LCF_k(l) problem with l=Omega(log^{2k+2}n) to a task involving m=O(n/log^{k+1}n) synchronized factors. The latter can be solved in O(m log^{k+1}m) time, which results in a linear-time algorithm for LCF_k(l) with l=Omega(log^{2k+2}n). In general, our solution to the LCF_k(l) problem for arbitrary l takes O(n + n log^{k+1} n/sqrt{l}) time.
@InProceedings{charalampopoulos_et_al:LIPIcs.CPM.2018.23,
author = {Charalampopoulos, Panagiotis and Crochemore, Maxime and Iliopoulos, Costas S. and Kociumaka, Tomasz and Pissis, Solon P. and Radoszewski, Jakub and Rytter, Wojciech and Walen, Tomasz},
title = {{Linear-Time Algorithm for Long LCF with k Mismatches}},
booktitle = {29th Annual Symposium on Combinatorial Pattern Matching (CPM 2018)},
pages = {23:1--23:16},
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.2018.23},
URN = {urn:nbn:de:0030-drops-86869},
doi = {10.4230/LIPIcs.CPM.2018.23},
annote = {Keywords: longest common factor, longest common substring, Hamming distance, heavy-light decomposition, difference cover}
}