String Indexing for Top-k Close Consecutive Occurrences

Autor: Bille, Philip, Gørtz, Inge Li, Pedersen, Max Rishøj, Rotenberg, Eva, Steiner, Teresa Anna
Přispěvatelé: Saxena, Nitin, Simon, Sunil
Jazyk: angličtina
Rok vydání: 2020
Předmět:
Zdroj: Bille, P, Gørtz, I L, Pedersen, M R, Rotenberg, E & Steiner, T A 2020, String indexing for top-k close consecutive occurrences . in N Saxena & S Simon (eds), Proceedings of 40 th IARCS Annual Conference on Foundations of Software Technology and Theoretical Computer Science ., 14, Schloss Dagstuhl-Leibniz-Zentrum fur Informatik GmbH, Dagstuhl Publishing, Leibniz International Proceedings in Informatics, LIPIcs, vol. 182, 40th IARCS Annual Conference on Foundations of Software Technology and Theoretical Computer Science, Virtual, Goa, India, 14/12/2020 . https://doi.org/10.4230/LIPIcs.FSTTCS.2020.14
Bille, P, Gørtz, I L, Pedersen, M R, Rotenberg, E & Steiner, T A 2022, ' String indexing for top-k close consecutive occurrences ', Theoretical Computer Science, vol. 927, pp. 133-147 . https://doi.org/10.1016/j.tcs.2022.06.004
DOI: 10.4230/lipics.fsttcs.2020.14
Popis: The classic string indexing problem is to preprocess a string $S$ into a compact data structure that supports efficient subsequent pattern matching queries, that is, given a pattern string $P$, report all occurrences of $P$ within $S$. In this paper, we study a basic and natural extension of string indexing called the string indexing for top-$k$ close consecutive occurrences problem (SITCCO). Here, a consecutive occurrence is a pair $(i,j)$, $i < j$, such that $P$ occurs at positions $i$ and $j$ in $S$ and there is no occurrence of $P$ between $i$ and $j$, and their distance is defined as $j-i$. Given a pattern $P$ and a parameter $k$, the goal is to report the top-$k$ consecutive occurrences of $P$ in $S$ of minimal distance. The challenge is to compactly represent $S$ while supporting queries in time close to length of $P$ and $k$. We give two time-space trade-offs for the problem. Let $n$ be the length of $S$, $m$ the length of $P$, and $\epsilon\in(0,1]$. Our first result achieves $O(n\log n)$ space and optimal query time of $O(m+k)$, and our second result achieves linear space and query time $O(m+k^{1+\epsilon})$. Along the way, we develop several techniques of independent interest, including a new translation of the problem into a line segment intersection problem and a new recursive clustering technique for trees.
Comment: Fixed typos, minor changes
Databáze: OpenAIRE