Fully Dynamic Strongly Connected Components in Planar Digraphs

Fuente: arXiv
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Main Authors: Karczmarz, Adam, Smulewicz, Marcin
Format: Preprint
Published: 2024
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author Karczmarz, Adam
Smulewicz, Marcin
author_facet Karczmarz, Adam
Smulewicz, Marcin
contents In this paper, we consider maintaining strongly connected components (SCCs) of a directed planar graph subject to edge insertions and deletions. We show a data structure maintaining an implicit representation of the SCCs within $\tilde{O}(n^{6/7})$ worst-case time per update. The data structure supports, in $O(\log^2{n})$ time, reporting vertices of any specified SCC (with constant overhead per reported vertex) and aggregating vertex information (e.g., computing the maximum label) over all the vertices of that SCC. Furthermore, it can maintain global information about the structure of SCCs, such as the number of SCCs or the size of the largest SCC. To the best of our knowledge, no fully dynamic SCCs data structures with sublinear update time have been previously known for any major subclass of digraphs. Our result should be contrasted with the known $n^{1-o(1)}$ amortized update time lower bound conditional on SETH, which holds even for dynamically maintaining whether a general digraph has more than two SCCs.
format Preprint
id arxiv_https___arxiv_org_abs_2406_10420
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Fully Dynamic Strongly Connected Components in Planar Digraphs
Karczmarz, Adam
Smulewicz, Marcin
Data Structures and Algorithms
In this paper, we consider maintaining strongly connected components (SCCs) of a directed planar graph subject to edge insertions and deletions. We show a data structure maintaining an implicit representation of the SCCs within $\tilde{O}(n^{6/7})$ worst-case time per update. The data structure supports, in $O(\log^2{n})$ time, reporting vertices of any specified SCC (with constant overhead per reported vertex) and aggregating vertex information (e.g., computing the maximum label) over all the vertices of that SCC. Furthermore, it can maintain global information about the structure of SCCs, such as the number of SCCs or the size of the largest SCC. To the best of our knowledge, no fully dynamic SCCs data structures with sublinear update time have been previously known for any major subclass of digraphs. Our result should be contrasted with the known $n^{1-o(1)}$ amortized update time lower bound conditional on SETH, which holds even for dynamically maintaining whether a general digraph has more than two SCCs.
title Fully Dynamic Strongly Connected Components in Planar Digraphs
topic Data Structures and Algorithms
url https://arxiv.org/abs/2406.10420