Randomized $\tilde{O}(m\sqrt{n})$ Bellman-Ford from Fineman and the Boilermakers

Fuente: arXiv
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Autore principale: Rao, Satish
Natura: Preprint
Pubblicazione: 2025
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author Rao, Satish
author_facet Rao, Satish
contents A classical algorithm by Bellman and Ford from the 1950's computes shortest paths in weighted graphs on $n$ vertices and $m$ edges with possibly negative weights in $O(mn)$ time. Indeed, this algorithm is taught regularly in undergraduate Algorithms courses. In 2023, after nearly 70 years, Fineman \cite{fineman2024single} developed an $\tilde{O}(m n^{8/9})$ expected time algorithm for this problem. Huang, Jin and Quanrud improved on Fineman's startling breakthrough by providing an $\tilde{O}(m n^{4/5} )$ time algorithm. This paper builds on ideas from those results to produce an $\tilde{O}(m\sqrt{n})$ expected time algorithm. The simple observation that distances can be updated with respect to the reduced costs for a price function in linear time is key to the improvement. This almost immediately improves the previous work. To produce the final bound, this paper provides recursive versions of Fineman's structures.
format Preprint
id arxiv_https___arxiv_org_abs_2503_22613
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Randomized $\tilde{O}(m\sqrt{n})$ Bellman-Ford from Fineman and the Boilermakers
Rao, Satish
Data Structures and Algorithms
Computational Complexity
A classical algorithm by Bellman and Ford from the 1950's computes shortest paths in weighted graphs on $n$ vertices and $m$ edges with possibly negative weights in $O(mn)$ time. Indeed, this algorithm is taught regularly in undergraduate Algorithms courses. In 2023, after nearly 70 years, Fineman \cite{fineman2024single} developed an $\tilde{O}(m n^{8/9})$ expected time algorithm for this problem. Huang, Jin and Quanrud improved on Fineman's startling breakthrough by providing an $\tilde{O}(m n^{4/5} )$ time algorithm. This paper builds on ideas from those results to produce an $\tilde{O}(m\sqrt{n})$ expected time algorithm. The simple observation that distances can be updated with respect to the reduced costs for a price function in linear time is key to the improvement. This almost immediately improves the previous work. To produce the final bound, this paper provides recursive versions of Fineman's structures.
title Randomized $\tilde{O}(m\sqrt{n})$ Bellman-Ford from Fineman and the Boilermakers
topic Data Structures and Algorithms
Computational Complexity
url https://arxiv.org/abs/2503.22613