Dynamic Parameterized Problems and Algorithms

© 2020 ACM. Fixed-parameter algorithms and kernelization are two powerful methods to solve NP-hard problems. Yet so far those algorithms have been largely restricted to static inputs. In this article, we provide fixed-parameter algorithms and kernelizations for fundamental NP-hard problems with dyna...

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Main Authors: Alman, Josh, Mnich, Matthias, Williams, Virginia Vassilevska
Format: Article
Language:English
Published: Association for Computing Machinery (ACM) 2021
Online Access:https://hdl.handle.net/1721.1/135282
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author Alman, Josh
Mnich, Matthias
Williams, Virginia Vassilevska
author_facet Alman, Josh
Mnich, Matthias
Williams, Virginia Vassilevska
author_sort Alman, Josh
collection MIT
description © 2020 ACM. Fixed-parameter algorithms and kernelization are two powerful methods to solve NP-hard problems. Yet so far those algorithms have been largely restricted to static inputs. In this article, we provide fixed-parameter algorithms and kernelizations for fundamental NP-hard problems with dynamic inputs. We consider a variety of parameterized graph and hitting set problems that are known to have f(k)n1+o(1) time algorithms on inputs of size n, and we consider the question of whether there is a data structure that supports small updates (such as edge/vertex/set/element insertions and deletions) with an update time of g(k)no(1); such an update time would be essentially optimal. Update and query times independent of n are particularly desirable. Among many other results, we show that FEEDBACK VERTEX SET and k-PATH admit dynamic algorithms with f(k)log O(1) update and query times for some function f depending on the solution size k only. We complement our positive results by several conditional and unconditional lower bounds. For example, we show that unlike their undirected counterparts, DIRECTED FEEDBACK VERTEX SET and DIRECTED k-PATH do not admit dynamic algorithms with no(1) update and query times even for constant solution sizes k ≤ 3, assuming popular hardness hypotheses. We also show that unconditionally, in the cell probe model, DIRECTED FEEDBACK VERTEX SET cannot be solved with update time that is purely a function of k.
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spelling mit-1721.1/1352822021-10-28T03:17:31Z Dynamic Parameterized Problems and Algorithms Alman, Josh Mnich, Matthias Williams, Virginia Vassilevska © 2020 ACM. Fixed-parameter algorithms and kernelization are two powerful methods to solve NP-hard problems. Yet so far those algorithms have been largely restricted to static inputs. In this article, we provide fixed-parameter algorithms and kernelizations for fundamental NP-hard problems with dynamic inputs. We consider a variety of parameterized graph and hitting set problems that are known to have f(k)n1+o(1) time algorithms on inputs of size n, and we consider the question of whether there is a data structure that supports small updates (such as edge/vertex/set/element insertions and deletions) with an update time of g(k)no(1); such an update time would be essentially optimal. Update and query times independent of n are particularly desirable. Among many other results, we show that FEEDBACK VERTEX SET and k-PATH admit dynamic algorithms with f(k)log O(1) update and query times for some function f depending on the solution size k only. We complement our positive results by several conditional and unconditional lower bounds. For example, we show that unlike their undirected counterparts, DIRECTED FEEDBACK VERTEX SET and DIRECTED k-PATH do not admit dynamic algorithms with no(1) update and query times even for constant solution sizes k ≤ 3, assuming popular hardness hypotheses. We also show that unconditionally, in the cell probe model, DIRECTED FEEDBACK VERTEX SET cannot be solved with update time that is purely a function of k. 2021-10-27T20:22:46Z 2021-10-27T20:22:46Z 2020 2021-01-25T17:31:59Z Article http://purl.org/eprint/type/JournalArticle https://hdl.handle.net/1721.1/135282 en 10.1145/3395037 ACM Transactions on Algorithms Creative Commons Attribution-Noncommercial-Share Alike http://creativecommons.org/licenses/by-nc-sa/4.0/ application/pdf Association for Computing Machinery (ACM) arXiv
spellingShingle Alman, Josh
Mnich, Matthias
Williams, Virginia Vassilevska
Dynamic Parameterized Problems and Algorithms
title Dynamic Parameterized Problems and Algorithms
title_full Dynamic Parameterized Problems and Algorithms
title_fullStr Dynamic Parameterized Problems and Algorithms
title_full_unstemmed Dynamic Parameterized Problems and Algorithms
title_short Dynamic Parameterized Problems and Algorithms
title_sort dynamic parameterized problems and algorithms
url https://hdl.handle.net/1721.1/135282
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