Oracles for bounded-length shortest paths in planar graphs

  • Authors:
  • Lukasz Kowalik;Maciej Kurowski

  • Affiliations:
  • Warsaw University, Warsaw, Poland;Warsaw University, Warsaw, Poland

  • Venue:
  • ACM Transactions on Algorithms (TALG)
  • Year:
  • 2006

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Abstract

We present a new approach for answering short path queries in planar graphs. For any fixed constant k and a given unweighted planar graph G = (V, E), one can build in O(|V|) time a data structure, which allows to check in O(1) time whether two given vertices are at distance at most k in G and if so a shortest path between them is returned. Graph G can be undirected as well as directed.Our data structure works in fully dynamic environment. It can be updated in O(1) time after removing an edge or a vertex while updating after an edge insertion takes polylogarithmic amortized time. Besides deleting elements one can also disable ones for some time. It is motivated by a practical situation where nodes or links of a network may be temporarily out of service.Our results can be easily generalized to other wide classes of graphs---for instance we can take any minor-closed family of graphs.