arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2403.04542cs.DS
收藏

有向扩张器分解的近最优算法

Near-Optimal Algorithm for Directed Expander Decompositions

Aurelio L. Sulser, Maximilian Probst Gutenberg

AI总结:

该研究提出首个近最优时间复杂度Õ(m)的有向扩张器分解算法,可动态维护分解并获近最优更新时间,通过新推-拉-重标记流框架改进前人算法,还可加速最小成本流及最大流等相关算法。

摘要:

在这项工作中,我们提出了第一个算法,用于在具有m条边的有向图中计算扩张器分解,其时间复杂度为Õ(m),接近最优。此外,我们的算法可以在动态图中维护这种分解,并再次获得接近最优的更新时间。我们的结果改进了之前Bernstein-Probst Gutenberg-Saranurak(FOCS 2020)、Hua-Kyng-Probst Gutenberg-Wu(SODA 2023)的算法,这些算法仅获得了在子多项式因子内最优的算法。为了获得新算法,我们提出了一种新的推-拉-重标记流框架,该框架推广了经典的推-重标记流算法Goldberg-Tarjan(JACM 1988),后者后来被动态化用于无向图中的扩张器分解(Henzinger-Rao-Wang,SIAM J. Comput. 2020;Saranurak-Wang,SODA 2019)。然后我们证明,最近Hua-Kyng-Probst Gutenberg-Wu(SODA 2023)工作中为分解有向图而提出的流问题,可以在推-拉-重标记流框架中更高效地解决。最近,我们的算法已被用于获得当前最快的最小成本流计算算法Van den Brand-Chen-Kyng-Liu-Probst Gutenberg-Sachdeva(FOCS 2024)。我们进一步认为,我们的算法可用于加速和简化组合图算法中最近的突破,以实现快速最大流算法(Chuzhoy-Khanna,SODA 2024;Chuzhoy-Khanna,STOC 2024;Bernstein-Blikstad-Saranurak-Tu,FOCS 2024)。

英文摘要:

In this work, we present the first algorithm to compute expander decompositions in an m-edge directed graph with near-optimal time Õ(m). Further, our algorithm can maintain such a decomposition in a dynamic graph and again obtains near-optimal update times. Our result improves over previous algorithms of Bernstein-Probst Gutenberg-Saranurak (FOCS 2020), Hua-Kyng-Probst Gutenberg-Wu (SODA 2023) that only obtained algorithms optimal up to subpolynomial factors. In order to obtain our new algorithm, we present a new push-pull-relabel flow framework that generalizes the classic push-relabel flow algorithm Goldberg-Tarjan (JACM 1988) which was later dynamized for computing expander decompositions in undirected graphs Henzinger-Rao-Wang (SIAM J. Comput. 2020), Saranurak-Wang (SODA 2019). We then show that the flow problems formulated in recent work Hua-Kyng-Probst Gutenberg-Wu (SODA 2023) to decompose directed graphs can be solved much more efficiently in the push-pull-relabel flow framework. Recently, our algorithm has already been employed to obtain the currently fastest algorithm to compute min-cost flows Van den Brand-Chen-Kyng-Liu-Probst Gutenberg-Sachdeva (FOCS 2024). We further believe that our algorithm can be used to speed-up and simplify recent breakthroughs in combinatorial graph algorithms towards fast maximum flow algorithms Chuzhoy-Khanna (SODA 2024), Chuzhoy-Khanna (STOC 2024), Bernstein-Blikstad-Saranurak-Tu (FOCS 2024).

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑