Algorithmica最新文献_第5页

Convergence of the Number of Period sets in Strings 字符串中周期集合数目的收敛性

IF 0.9 4区计算机科学

Algorithmica Pub Date : 2025-02-21 DOI: 10.1007/s00453-025-01295-y

Eric Rivals, Michelle Sweering, Pengfei Wang

{"title":"Convergence of the Number of Period sets in Strings","authors":"Eric Rivals, Michelle Sweering, Pengfei Wang","doi":"10.1007/s00453-025-01295-y","DOIUrl":"10.1007/s00453-025-01295-y","url":null,"abstract":"<div>Consider words of length n. The set of all periods of a word of length n is a subset of ({0,1,2,ldots ,n-1}). However, not every subset of ({0,1,2,ldots ,n-1}) can be a valid set of periods. In a seminal paper in 1981, Guibas and Odlyzko proposed encoding the set of periods of a word into a binary string of length n, called an autocorrelation, where a 1 at position i denotes the period i. They considered the question of recognizing a valid period set, and also studied the number (kappa _n) of valid period sets for strings of length n. They conjectured that (ln kappa _n) asymptotically converges to a constant times ((ln n)^2). Although improved lower bounds for (ln kappa _n/(ln n)^2) were proved in 2001, the question of a tight upper bound has remained open since Guibas and Odlyzko’s paper. Here, we exhibit an upper bound for this fraction, which implies its convergence and closes this longstanding conjecture. Moreover, we extend our result to find similar bounds for the number of correlations: a generalization of autocorrelations that encodes the overlaps between two strings.\u0000</div>","PeriodicalId":50824,"journal":{"name":"Algorithmica","volume":"87 5","pages":"690 - 711"},"PeriodicalIF":0.9,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143918966","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Analysis of the (1+1) EA on LeadingOnes with Constraints 带约束导联器的（1+1）EA分析

IF 0.9 4区计算机科学

Algorithmica Pub Date : 2025-02-19 DOI: 10.1007/s00453-025-01298-9

Tobias Friedrich, Timo Kötzing, Aneta Neumann, Frank Neumann, Aishwarya Radhakrishnan

引用次数: 0

Tight Bounds for Chordal/Interval Vertex Deletion Parameterized by Treewidth 由Treewidth参数化的弦/间隔顶点删除紧边界

IF 0.9 4区计算机科学

Algorithmica Pub Date : 2025-01-29 DOI: 10.1007/s00453-025-01293-0

Michał Włodarczyk

引用次数: 0

Correction: Galloping in Fast-Growth Natural Merge Sorts 更正：在快速增长的自然合并分类中驰骋

IF 0.9 4区计算机科学

Algorithmica Pub Date : 2025-01-29 DOI: 10.1007/s00453-025-01297-w

Elahe Ghasemi, Vincent Jugé, Ghazal Khalighinejad, Helia Yazdanyar

引用次数: 0

Reforming an Envy-Free Matching 改革无嫉妒的配对

IF 0.9 4区计算机科学

Algorithmica Pub Date : 2025-01-27 DOI: 10.1007/s00453-025-01294-z

Takehiro Ito, Yuni Iwamasa, Naonori Kakimura, Naoyuki Kamiyama, Yusuke Kobayashi, Yuta Nozaki, Yoshio Okamoto, Kenta Ozeki

引用次数: 0

Guarding Polyominoes Under k-Hop Visibility 在k-Hop能见度下保护多米诺

IF 0.9 4区计算机科学

Algorithmica Pub Date : 2025-01-11 DOI: 10.1007/s00453-024-01292-7

Omrit Filtser, Erik Krohn, Bengt J. Nilsson, Christian Rieck, Christiane Schmidt

引用次数: 0

Fixed Parameter Multi-Objective Evolutionary Algorithms for the W-Separator Problem w -分离器问题的固定参数多目标进化算法

IF 0.9 4区计算机科学

Algorithmica Pub Date : 2025-01-08 DOI: 10.1007/s00453-024-01290-9

Samuel Baguley, Tobias Friedrich, Aneta Neumann, Frank Neumann, Marcus Pappik, Ziena Zeif

{"title":"Fixed Parameter Multi-Objective Evolutionary Algorithms for the W-Separator Problem","authors":"Samuel Baguley, Tobias Friedrich, Aneta Neumann, Frank Neumann, Marcus Pappik, Ziena Zeif","doi":"10.1007/s00453-024-01290-9","DOIUrl":"10.1007/s00453-024-01290-9","url":null,"abstract":"<div>Parameterized analysis provides powerful mechanisms for obtaining fine-grained insights into different types of algorithms. In this work, we combine this field with evolutionary algorithms and provide parameterized complexity analysis of evolutionary multi-objective algorithms for the W-separator problem, which is a natural generalization of the vertex cover problem. The goal is to remove the minimum number of vertices such that each connected component in the resulting graph has at most W vertices. We provide different multi-objective formulations involving two or three objectives that provably lead to fixed-parameter evolutionary algorithms with respect to the value of an optimal solution OPT and W. Of particular interest are kernelizations and the reducible structures used for them. We show that in expectation the algorithms make incremental progress in finding such structures and beyond. The current best known kernelization of the W-separator uses linear programming methods and requires non-trivial post-processing steps to extract the reducible structures. We provide additional structural features to show that evolutionary algorithms with appropriate objectives are also capable of extracting them. Our results show that evolutionary algorithms with different objectives guide the search and admit fixed parameterized runtimes to solve or approximate (even arbitrarily close) the W-separator problem.</div>","PeriodicalId":50824,"journal":{"name":"Algorithmica","volume":"87 4","pages":"537 - 571"},"PeriodicalIF":0.9,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00453-024-01290-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143668295","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Complexity Framework for Forbidden Subgraphs I: The Framework 禁止子图的复杂度框架I：框架

IF 0.9 4区计算机科学

Algorithmica Pub Date : 2025-01-05 DOI: 10.1007/s00453-024-01289-2

Matthew Johnson, Barnaby Martin, Jelle J. Oostveen, Sukanya Pandey, Daniël Paulusma, Siani Smith, Erik Jan van Leeuwen

{"title":"Complexity Framework for Forbidden Subgraphs I: The Framework","authors":"Matthew Johnson, Barnaby Martin, Jelle J. Oostveen, Sukanya Pandey, Daniël Paulusma, Siani Smith, Erik Jan van Leeuwen","doi":"10.1007/s00453-024-01289-2","DOIUrl":"10.1007/s00453-024-01289-2","url":null,"abstract":"<div>For a set of graphs ({mathcal {H}}), a graph G is ({mathcal {H}})-subgraph-free if G does not contain any graph from ({{{mathcal {H}}}}) as a subgraph. We propose general and easy-to-state conditions on graph problems that explain a large set of results for ({mathcal {H}})-subgraph-free graphs. Namely, a graph problem must be efficiently solvable on graphs of bounded treewidth, computationally hard on subcubic graphs, and computational hardness must be preserved under edge subdivision of subcubic graphs. Our meta-classification says that if a graph problem (Pi ) satisfies all three conditions, then for every finite set ({{{mathcal {H}}}}), it is “efficiently solvable” on ({{{mathcal {H}}}})-subgraph-free graphs if ({mathcal {H}}) contains a disjoint union of one or more paths and subdivided claws, and (Pi ) is “computationally hard” otherwise. We apply our meta-classification on many well-known partitioning, covering and packing problems, network design problems and width parameter problems to obtain a dichotomy between polynomial-time solvability and NP-completeness. For distance-metric problems, we obtain a dichotomy between almost-linear-time solvability and having no subquadratic-time algorithm (conditioned on some hardness hypotheses). Apart from capturing a large number of explicitly and implicitly known results in the literature, we also prove a number of new results. Moreover, we perform an extensive comparison between the subgraph framework and the existing frameworks for the minor and topological minor relations, and pose several new open problems and research directions.\u0000</div>","PeriodicalId":50824,"journal":{"name":"Algorithmica","volume":"87 3","pages":"429 - 464"},"PeriodicalIF":0.9,"publicationDate":"2025-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00453-024-01289-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143446414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

FREIGHT: Fast Streaming Hypergraph Partitioning 快速流超图分区

IF 0.9 4区计算机科学

Algorithmica Pub Date : 2025-01-03 DOI: 10.1007/s00453-024-01291-8

Kamal Eyubov, Marcelo Fonseca Faraj, Christian Schulz

{"title":"FREIGHT: Fast Streaming Hypergraph Partitioning","authors":"Kamal Eyubov, Marcelo Fonseca Faraj, Christian Schulz","doi":"10.1007/s00453-024-01291-8","DOIUrl":"10.1007/s00453-024-01291-8","url":null,"abstract":"<div>Partitioning the vertices of a (hyper)graph into k roughly balanced blocks such that few (hyper)edges run between blocks is a key problem for large-scale distributed processing. A current trend for partitioning huge (hyper)graphs using low computational resources are streaming algorithms. In this work, we propose FREIGHT: a Fast stREamInG Hypergraph parTitioning algorithm which is an adaptation of the widely-known graph-based algorithm Fennel. By using an efficient data structure, we make the overall running of FREIGHT linearly dependent on the pin-count of the hypergraph and the memory consumption linearly dependent on the numbers of nets and blocks. The results of our extensive experimentation showcase the promising performance of FREIGHT as a highly efficient and effective solution for streaming hypergraph partitioning. Our algorithm demonstrates competitive running time with the Hashing algorithm, with a geometric mean runtime within a factor of four compared to the Hashing algorithm. Significantly, our findings highlight the superiority of FREIGHT over all existing (buffered) streaming algorithms and even the in-memory algorithm HYPE, with respect to both cut-net and connectivity measures. This indicates that our proposed algorithm is a promising hypergraph partitioning tool to tackle the challenge posed by large-scale and dynamic data processing.</div>","PeriodicalId":50824,"journal":{"name":"Algorithmica","volume":"87 3","pages":"405 - 428"},"PeriodicalIF":0.9,"publicationDate":"2025-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00453-024-01291-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143446391","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

An Efficient Algorithm for Power Dominating Set 一种有效的幂控制集算法

IF 0.9 4区计算机科学

Algorithmica Pub Date : 2024-12-23 DOI: 10.1007/s00453-024-01283-8

Thomas Bläsius, Max Göttlicher

{"title":"An Efficient Algorithm for Power Dominating Set","authors":"Thomas Bläsius, Max Göttlicher","doi":"10.1007/s00453-024-01283-8","DOIUrl":"10.1007/s00453-024-01283-8","url":null,"abstract":"<div>The problem Power Dominating Set (PDS) is motivated by the placement of phasor measurement units to monitor electrical networks. It asks for a minimum set of vertices in a graph that observes all remaining vertices by exhaustively applying two observation rules. Our contribution is twofold. First, we determine the parameterized complexity of PDS by proving it is W[P]-complete when parameterized with respect to the solution size. We note that it was only known to be W[2]-hard before. Our second and main contribution is a new algorithm for PDS that efficiently solves practical instances. Our algorithm consists of two complementary parts. The first is a set of reduction rules for PDS that can also be used in conjunction with previously existing algorithms. The second is an algorithm for solving the remaining kernel based on the implicit hitting set approach. Our evaluation on a set of power grid instances from the literature shows that our solver outperforms previous state-of-the-art solvers for PDS by more than one order of magnitude on average. Furthermore, our algorithm can solve previously unsolved instances of continental scale within a few minutes.</div>","PeriodicalId":50824,"journal":{"name":"Algorithmica","volume":"87 3","pages":"344 - 376"},"PeriodicalIF":0.9,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00453-024-01283-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143446557","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0