On Dynamic Shortest Paths Problems

We obtain the following results related to dynamic versions of the shortest-paths problem: Reductions that show that the incremental and decremental single-source shortest-paths problems, for weighted directed or undirected graphs, are, in a strong sense, at least as hard as the static all-pairs sho...

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Bibliographic Details
Published in:Algorithmica Vol. 61; no. 2; pp. 389 - 401
Main Authors: Roditty, Liam, Zwick, Uri
Format: Journal Article
Language:English
Published: New York Springer-Verlag 01.10.2011
Springer
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ISSN:0178-4617, 1432-0541
Online Access:Get full text
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Summary:We obtain the following results related to dynamic versions of the shortest-paths problem: Reductions that show that the incremental and decremental single-source shortest-paths problems, for weighted directed or undirected graphs, are, in a strong sense, at least as hard as the static all-pairs shortest-paths problem. We also obtain slightly weaker results for the corresponding unweighted problems. A randomized fully-dynamic algorithm for the all-pairs shortest-paths problem in directed unweighted graphs with an amortized update time of (we use to hide small poly-logarithmic factors) and a worst case query time is O ( n 3/4 ). A deterministic O ( n 2 log  n ) time algorithm for constructing an O (log  n )-spanner with O ( n ) edges for any weighted undirected graph on n vertices. The algorithm uses a simple algorithm for incrementally maintaining single-source shortest-paths tree up to a given distance.
ISSN:0178-4617
1432-0541
DOI:10.1007/s00453-010-9401-5