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Efficient construction of hierarchical overlap graphs. (English) Zbl 1511.68104

Boucher, Christina (ed.) et al., String processing and information retrieval. 27th international symposium, SPIRE 2020, Orlando, FL, USA, October 13–15, 2020. Proceedings. Cham: Springer. Lect. Notes Comput. Sci. 12303, 277-290 (2020).
Summary: The hierarchical overlap graph (HOG for short) is an overlap encoding graph that efficiently represents overlaps from a given set \(P\) of \(n\) strings. A previously known algorithm constructs the HOG in \(O(\vert \vert P \vert \vert + n^2)\) time and \(O(\vert \vert P \vert \vert +n\times \min (n,\max \{|s|:s\in P\}))\) space, where \(\vert \vert P \vert \vert\) is the sum of lengths of the \(n\) strings in \(P\). We present a new algorithm of \(O(\vert \vert P \vert \vert \log n)\) time and \(O(\vert \vert P \vert \vert )\) space to compute the HOG, which exploits the segment tree data structure. We also propose an alternative algorithm using \(O(\vert \vert P \vert \vert \frac{\log n}{\log \log n})\) time and \(O(\vert \vert P \vert \vert )\) space in the word RAM model of computation.
For the entire collection see [Zbl 1502.68020].

MSC:

68P05 Data structures
68W32 Algorithms on strings