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We present two algorithms for maintaining the topological order of a directed acyclic graph with n vertices, under an online edge insertion sequence of m edges. Efficient algorithms for online topological ordering have many applications,…

Data Structures and Algorithms · Computer Science 2007-11-05 Telikepalli Kavitha , Rogers Mathew

Given a graph $G=(V, E)$, the problem of Graph Burning is to find a sequence of nodes from $V$, called a burning sequence, to burn the whole graph. This is a discrete-step process, and at each step, an unburned vertex is selected as an…

Data Structures and Algorithms · Computer Science 2023-07-18 Rahul Kumar Gautam , Anjeneya Swami Kare , S. Durga Bhavani

Suppose we have a network that is represented by a graph $G$. Potentially a fire (or other type of contagion) might erupt at some vertex of $G$. We are able to respond to this outbreak by establishing a firebreak at $k$ other vertices of…

We study the $b$-matching problem in bipartite graphs $G=(S,R,E)$. Each vertex $s\in S$ is a server with individual capacity $b_s$. The vertices $r\in R$ are requests that arrive online and must be assigned instantly to an eligible server.…

Data Structures and Algorithms · Computer Science 2022-07-01 Susanne Albers , Sebastian Schubert

The firefighter problem with $k$ firefighters on an infinite graph $G$ is an iterative graph process, defined as follows: Suppose a fire breaks out at a given vertex $v\in V(G)$ on Turn 1. On each subsequent even turn, $k$ firefighters…

In this paper, we consider the \emph{firefighter problem} on a graph $G=(V,E)$ that is either finite or infinite. Suppose that a fire breaks out at a given vertex $v \in V$. In each subsequent time unit, a firefighter protects one vertex…

Combinatorics · Mathematics 2014-06-20 Tomas Gavenciak , Jan Kratochvil , Pawel Pralat

Continuous and discrete models for firefighting problems are well-studied in Theoretical Computer Science. We introduce a new, discrete, and more general framework based on a hexagonal cell graph to study firefighting problems in varied…

Computational Geometry · Computer Science 2019-11-26 Rolf Klein , David Kübel , Elmar Langetepe , Jörg-Rüdiger Sack , Barbara Schwarzwald

We study a version of online edge coloring, where the goal is to color as many edges as possible using only a given number, $k$, of available colors. All of our results are with regard to competitive analysis. Previous attempts to identify…

Data Structures and Algorithms · Computer Science 2016-10-26 Lene M. Favrholdt , Jesper W. Mikkelsen

The {Congested Clique} is a distributed-computing model for single-hop networks with restricted bandwidth that has been very intensively studied recently. It models a network by an $n$-vertex graph in which any pair of vertices can…

Distributed, Parallel, and Cluster Computing · Computer Science 2018-02-21 Leonid Barenboim , Victor Khazanov

The Firefighting problem is defined as follows. At time $t=0$, a fire breaks out at a vertex of a graph. At each time step $t \geq 0$, a firefighter permanently defends (protects) an unburned vertex, and the fire then spread to all…

Data Structures and Algorithms · Computer Science 2017-11-29 Bireswar Das , Murali Krishna Enduri , Neeldhara Misra , I. Vinod Reddy

Online computation is a concept to model uncertainty where not all information on a problem instance is known in advance. An online algorithm receives requests which reveal the instance piecewise and has to respond with irrevocable…

Computational Complexity · Computer Science 2023-11-28 Janosch Fuchs , Christoph Grüne , Tom Janßen

This paper is devoted to the online dominating set problem and its variants. We believe the paper represents the first systematic study of the effect of two limitations of online algorithms: making irrevocable decisions while not knowing…

Data Structures and Algorithms · Computer Science 2018-09-14 Joan Boyar , Stephan J. Eidenbenz , Lene M. Favrholdt , Michal Kotrbčík , Kim S. Larsen

Online bipartite matching is a classical problem in online algorithms and we know that both the deterministic fractional and randomized integral online matchings achieve the same competitive ratio of $1-\frac{1}{e}$. In this work, we study…

Data Structures and Algorithms · Computer Science 2025-11-21 Amey Bhangale , Arghya Chakraborty , Prahladh Harsha

We initiate the study of a natural and practically relevant new variant of online caching where the to-be-cached items can have dependencies. We assume that the universe is a tree T and items are tree nodes; we require that if a node v is…

Data Structures and Algorithms · Computer Science 2017-05-16 Marcin Bienkowski , Jan Marcinkowski , Maciej Pacut , Stefan Schmid , Aleksandra Spyra

We introduce a fully online model of maximum cardinality matching in which all vertices arrive online. On the arrival of a vertex, its incident edges to previously-arrived vertices are revealed. Each vertex has a deadline that is after all…

Data Structures and Algorithms · Computer Science 2018-02-13 Zhiyi Huang , Ning Kang , Zhihao Gavin Tang , Xiaowei Wu , Yuhao Zhang , Xue Zhu

In the online bipartite matching with reassignments problem, an algorithm is initially given only one side of the vertex set of a bipartite graph; the vertices on the other side are revealed to the algorithm one by one, along with its…

Data Structures and Algorithms · Computer Science 2020-03-12 Yongho Shin , Kangsan Kim , Seungmin Lee , Hyung-Chan An

We consider the complexity of the firefighter problem where b>=1 firefighters are available at each time step. This problem is proved NP-complete even on trees of degree at most three and budget one (Finbow et al.,2007) and on trees of…

Discrete Mathematics · Computer Science 2014-04-29 Janka Chlebíková , Morgan Chopin

In the Telephone Broadcasting problem, the goal is to disseminate a message from a given source vertex of an input graph to all other vertices in the minimum number of rounds, where at each round, an informed vertex can send the message to…

Data Structures and Algorithms · Computer Science 2025-02-12 Aida Aminian , Shahin Kamali , Seyed-Mohammad Seyed-Javadi , Sumedha

We use Hartnell's model for virus spread on a graph, also known as firefighting. For rooted trees, we propose an Unburning Algorithm, a type of greedy algorithm starting from the leaves and working back towards the root. We show that the…

Combinatorics · Mathematics 2024-09-24 Andrea Barnett , Robert Bond , Anthony Macias , Thomas W. Mattman , Bill Parnell , Ely Schoenfield

We study space and time efficient quantum algorithms for two graph problems -- deciding whether an $n$-vertex graph is a forest, and whether it is bipartite. Via a reduction to the s-t connectivity problem, we describe quantum algorithms…

Quantum Physics · Physics 2016-10-04 Chris Cade , Ashley Montanaro , Aleksandrs Belovs