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We give a new data structure for the fully-dynamic minimum spanning forest problem in simple graphs. Edge updates are supported in $O(\log^4n/\log\log n)$ amortized time per operation, improving the $O(\log^4n)$ amortized bound of Holm et…

Data Structures and Algorithms · Computer Science 2014-07-28 Jacob Holm , Eva Rotenberg , Christian Wulff-Nilsen

We present a decremental data structure for maintaining the SPQR-tree of a planar graph subject to edge contractions and deletions. The update time, amortized over $\Omega(n)$ operations, is $O(\log^2 n)$. Via SPQR-trees, we give a…

Data Structures and Algorithms · Computer Science 2018-06-29 Jacob Holm , Giuseppe F. Italiano , Adam Karczmarz , Jakub Łącki , Eva Rotenberg

The maximum common subtree isomorphism problem asks for the largest possible isomorphism between subtrees of two given input trees. This problem is a natural restriction of the maximum common subgraph problem, which is ${\sf NP}$-hard in…

Data Structures and Algorithms · Computer Science 2016-08-23 Andre Droschinsky , Nils M. Kriege , Petra Mutzel

We give two fully dynamic algorithms that maintain a $(1+\varepsilon)$-approximation of the weight $M$ of a minimum spanning forest (MSF) of an $n$-node graph $G$ with edges weights in $[1,W]$, for any $\varepsilon>0$. (1) Our deterministic…

Data Structures and Algorithms · Computer Science 2021-09-29 Monika Henzinger , Pan Peng

In this paper we study the Steiner tree problem over a dynamic set of terminals. We consider the model where we are given an $n$-vertex graph $G=(V,E,w)$ with positive real edge weights, and our goal is to maintain a tree which is a good…

Data Structures and Algorithms · Computer Science 2016-06-27 Jakub Łącki , Jakub Oćwieja , Marcin Pilipczuk , Piotr Sankowski , Anna Zych

We present time-efficient distributed algorithms for decomposing graphs with large edge or vertex connectivity into multiple spanning or dominating trees, respectively. As their primary applications, these decompositions allow us to achieve…

Data Structures and Algorithms · Computer Science 2013-11-22 Keren Censor-Hillel , Mohsen Ghaffari , Fabian Kuhn

We describe a framework for maintaining forest algebra representations that are of logarithmic height for unranked trees. Such representations can be computed in O(n) time and updated in O(log(n)) time. The framework is of potential…

Logic in Computer Science · Computer Science 2025-10-08 Sarah Kleest-Meißner , Jonas Marasus , Matthias Niewerth

Tree edit distance is a well-studied measure of dissimilarity between rooted trees with node labels. It can be computed in $O(n^3)$ time [Demaine, Mozes, Rossman, and Weimann, ICALP 2007], and fine-grained hardness results suggest that the…

Data Structures and Algorithms · Computer Science 2021-06-11 Shyan Akmal , Ce Jin

In this paper we show a new algorithm for the decremental single-source reachability problem in directed planar graphs. It processes any sequence of edge deletions in $O(n\log^2{n}\log\log{n})$ total time and explicitly maintains the set of…

Data Structures and Algorithms · Computer Science 2017-06-01 Giuseppe F. Italiano , Adam Karczmarz , Jakub Łącki , Piotr Sankowski

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

Dynamic programming is widely used for exact computations based on tree decompositions of graphs. However, the space complexity is usually exponential in the treewidth. We study the problem of designing efficient dynamic programming…

Data Structures and Algorithms · Computer Science 2014-06-16 Martin Furer , Huiwen Yu

Motivated by recent applications of dominator computations, we consider the problem of dynamically maintaining the dominators of flow graphs through a sequence of insertions and deletions of edges. Our main theoretical contribution is a…

Data Structures and Algorithms · Computer Science 2016-04-12 Loukas Georgiadis , Giuseppe F. Italiano , Luigi Laura , Federico Santaroni

We consider a new Steiner tree problem, called vertex-cover-weighted Steiner tree problem. This problem defines the weight of a Steiner tree as the minimum weight of vertex covers in the tree, and seeks a minimum-weight Steiner tree in a…

Data Structures and Algorithms · Computer Science 2018-08-08 Takuro Fukunaga , Takanori Maehara

With few exceptions (namely, algorithms for maximal matching, $2$-approximate vertex cover, and certain constant-stretch spanners), all known fully dynamic algorithms in general graphs require (amortized) $\Omega(\log n)$ update/query time.…

Data Structures and Algorithms · Computer Science 2019-07-11 Monika Henzinger , Pan Peng

We revisit the \textsc{$k$-Secluded Tree} problem. Given a vertex-weighted undirected graph $G$, its objective is to find a maximum-weight induced subtree $T$ whose open neighborhood has size at most $k$. We present a fixed-parameter…

Data Structures and Algorithms · Computer Science 2022-06-27 Huib Donkers , Bart M. P. Jansen , Jari J. H. de Kroon

The independence number of a tree decomposition is the maximum of the independence numbers of the subgraphs induced by its bags. The tree-independence number of a graph is the minimum independence number of a tree decomposition of it.…

Data Structures and Algorithms · Computer Science 2025-09-11 Clément Dallard , Fedor V. Fomin , Petr A. Golovach , Tuukka Korhonen , Martin Milanič

In this paper we describe a randomized algorithm which returns a maximal spanning forest of an unknown {\em weighted} undirected graph making $O(n)$ $\mathsf{CUT}$ queries in expectation. For weighted graphs, this is optimal due to a result…

Data Structures and Algorithms · Computer Science 2023-06-21 Hang Liao , Deeparnab Chakrabarty

We show fast deterministic algorithms for fundamental problems on forests in the challenging low-space regime of the well-known Massive Parallel Computation (MPC) model. A recent breakthrough result by Coy and Czumaj [STOC'22] shows that,…

Distributed, Parallel, and Cluster Computing · Computer Science 2022-11-08 Alkida Balliu , Rustam Latypov , Yannic Maus , Dennis Olivetti , Jara Uitto

We present two algorithms for dynamically maintaining a spanning forest of a graph undergoing edge insertions and deletions. Our algorithms guarantee {\em worst-case update time} and work against an adaptive adversary, meaning that an edge…

Data Structures and Algorithms · Computer Science 2017-04-19 Danupon Nanongkai , Thatchaphol Saranurak

We study the parameterized complexity of various classic vertex-deletion problems such as Odd cycle transversal, Vertex planarization, and Chordal vertex deletion under hybrid parameterizations. Existing FPT algorithms for these problems…

Data Structures and Algorithms · Computer Science 2022-07-19 Bart M. P. Jansen , Jari J. H. de Kroon , Michał Włodarczyk