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Related papers: $r$-indexing Wheeler graphs

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Let $T [1..n]$ be a text over an alphabet of size $\sigma \in \mathrm{polylog} (n)$, let $r^*$ be the sum of the numbers of runs in the Burrows-Wheeler Transforms of $T$ and its reverse, and let $z$ be the number of phrases in the LZ77…

Data Structures and Algorithms · Computer Science 2025-08-19 Travis Gagie

Motivated by challenges in pangenomic read alignment, we propose a generalization of Wheeler graphs that we call Wheeler maps. A Wheeler map stores a text $T[1..n]$ and an assignment of tags to the characters of $T$ such that we can…

Data Structures and Algorithms · Computer Science 2023-08-22 Andrej Baláz , Travis Gagie , Adrián Goga , Simon Heumos , Gonzalo Navarro , Alessia Petescia , Jouni Sirén

Computing the directed path-width of a directed graph is an NP-hard problem. Even for digraphs of maximum semi-degree 3 the problem remains hard. We propose a decomposition of an input digraph G=(V,A) by a number k of sequences with entries…

Data Structures and Algorithms · Computer Science 2018-11-07 Frank Gurski , Carolin Rehs , Jochen Rethmann

Let $G$ be a unit disk graph in the plane defined by $n$ disks whose positions are known. For the case when $G$ is unweighted, we give a simple algorithm to compute a shortest path tree from a given source in $O(n\log n)$ time. For the case…

Computational Geometry · Computer Science 2014-11-19 Sergio Cabello , Miha Jejčič

Given a planar graph $G$, we consider drawings of $G$ in the plane where edges are represented by straight line segments (which possibly intersect). Such a drawing is specified by an injective embedding $\pi$ of the vertex set of $G$ into…

Discrete Mathematics · Computer Science 2011-05-20 Mihyun Kang , Oleg Pikhurko , Alexander Ravsky , Mathias Schacht , Oleg Verbitsky

In recent years several compressed indexes based on variants of the Burrows-Wheeler transformation have been introduced. Some of these index structures far more complex than a single string, as was originally done with the FM-index…

Computational Complexity · Computer Science 2019-02-27 Daniel Gibney , Sharma V. Thankachan

The Burrows-Wheeler Transform (BWT) is an important technique both in data compression and in the design of compact indexing data structures. It has been generalized from single strings to collections of strings and some classes of labeled…

Data Structures and Algorithms · Computer Science 2019-05-30 Jarno Alanko , Travis Gagie , Gonzalo Navarro , Louisa Seelbach Benkner

We show how to merge two run-length compressed Burrows-Wheeler Transforms (RLBWTs) into a run-length compressed extended Burrows-Wheeler Transform (eBWT) in $O (r)$ space and $O ((r + L) \log (m + n))$ time, where $m$ and $n$ are the…

Data Structures and Algorithms · Computer Science 2026-04-16 Travis Gagie

We show how to store a searchable partial-sums data structure with constant query time for a static sequence $S$ of $n$ positive integers in $o \left( \frac{\log n}{(\log \log n)^2} \right)$, in $n H_k (S) + o (n)$ bits for $k \in o \left(…

Data Structures and Algorithms · Computer Science 2022-08-23 Travis Gagie

In this paper, we show that given a weighted, directed planar graph $G$, and any $\epsilon >0$, there exists a polynomial time and $O(n^{\frac{1}{2}+\epsilon})$ space algorithm that computes the shortest path between two fixed vertices in…

Computational Complexity · Computer Science 2015-02-10 Diptarka Chakraborty , Raghunath Tewari

We solve the following problem: Can an undirected weighted graph G be parti- tioned into two non-empty induced subgraphs satisfying minimum constraints for the sum of edge weights at vertices of each subgraph? We show that this is possible…

Combinatorics · Mathematics 2017-02-02 Amir Ban

We prove that, up to subpolynomial or polylogarithmic factors, there is no tradeoff between preprocessing time, query time, and size of exact distance oracles for planar graphs. Namely, we show how given an $n$-vertex weighted directed…

Data Structures and Algorithms · Computer Science 2026-03-30 Shay Mozes , Daniel Prigan

We initiate the study of computational problems on $k$-mers (strings of length $k$) in labeled graphs. As a starting point, we consider the problem of counting the number of distinct $k$-mers found on the walks of a graph. We establish that…

Data Structures and Algorithms · Computer Science 2026-02-23 Jarno N. Alanko , Maximo Perez-Lopez

Let $P \subset \mathbb{R}^2$ be a planar $n$-point set such that each point $p \in P$ has an associated radius $r_p > 0$. The transmission graph $G$ for $P$ is the directed graph with vertex set $P$ such that for any $p, q \in P$, there is…

Computational Geometry · Computer Science 2020-10-05 Haim Kaplan , Wolfgang Mulzer , Liam Roditty , Paul Seiferth

We present an algorithm to count the number of occurrences of a pattern graph $H$ as an induced subgraph in a host graph $G$. If $G$ belongs to a bounded expansion class, the algorithm runs in linear time. Our design choices are motivated…

Data Structures and Algorithms · Computer Science 2020-01-16 Felix Reidl , Blair D. Sullivan

Motivated by longstanding conjectures regarding decompositions of graphs into paths and cycles, we prove the following optimal decomposition results for random graphs. Let $0<p<1$ be constant and let $G\sim G_{n,p}$. Let $odd(G)$ be the…

Combinatorics · Mathematics 2016-06-21 Stefan Glock , Daniela Kühn , Deryk Osthus

Variation graphs, which represent genetic variation within a population, are replacing sequences as reference genomes. Path indexes are one of the most important tools for working with variation graphs. They generalize text indexes to…

Data Structures and Algorithms · Computer Science 2017-01-13 Jouni Sirén

Given a string $T$ on an alphabet of size $\sigma$, we describe a bidirectional Burrows-Wheeler index that takes $O(|T|\log{\sigma})$ bits of space, and that supports the addition \emph{and removal} of one character, on the left or right…

Data Structures and Algorithms · Computer Science 2019-06-11 Fabio Cunial , Djamal Belazzougui

For a graph G and integer r\geq 1 we denote the collection of independent r-sets of G by I^{(r)}(G). If v\in V(G) then I_v^{(r)}(G) is the collection of all independent r-sets containing v. A graph G, is said to be r-EKR, for r\geq 1, iff…

Combinatorics · Mathematics 2007-05-23 Fred Holroyd , John Talbot

We consider the following problem for oriented graphs and digraphs: Given an oriented graph (digraph) $G$, does it contain an induced subdivision of a prescribed digraph $D$? The complexity of this problem depends on $D$ and on whether $G$…

Discrete Mathematics · Computer Science 2016-03-27 Jørgen Bang-Jensen , Frédéric Havet , Nicolas Trotignon
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