Algorithms for dense graphs and networks on the random access computer (original) (raw)

Abstract

We improve upon the running time of several graph and network algorithms when applied to dense graphs. In particular, we show how to compute on a machine with word size λ=Ω (log_n_) a maximal matching in an_n_-vertex bipartite graph in time_O_(n 2+n 2.5/λ)=O(n 2.5/log_n_), how to compute the transitive closure of a digraph with_n_ vertices and_m_ edges in time_O_(n 2+nm/λ), how to solve the uncapacitated transportation problem with integer costs in the range [O.C_] and integer demands in the range [−_U.U_] in time_O ((n 3 (log log/log_n_)1/2+n2 log_U_) log_nC_), and how to solve the assignment problem with integer costs in the range [O.C_] in time_O(n 2.5 log_nC_/(log_n_/loglog_n_)1/4).

Assuming a suitably compressed input, we also show how to do depth-first and breadth-first search and how to compute strongly connected components and biconnected components in time_O(nλ+n_ 2/λ), and how to solve the single source shortest-path problem with integer costs in the range [O.C_] in time_0 (n 2(log_C_)/log_n_). For the transitive closure algorithm we also report on the experiences with an implementation.

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Authors and Affiliations

  1. Department of Combinatorics and Optimization, University of Waterloo, N2L 3G1, Waterloo, Ontario, Canada
    J. Cheriyan
  2. Max-Planck-Institut für Informatik and Universität des Saarlandes, D-66123, Saarbrücken, Germany
    K. Mehlhorn

Authors

  1. J. Cheriyan
  2. K. Mehlhorn

Additional information

Communicated by R. Sedgewick.

Most of this research was carried out while both authors worked at the Fachbereich Informatik, Universität des Saarlandes, Saarbrücken, Germany. The research was supported in part by ESPRIT Project No. 3075 ALCOM. The first author acknowledges support also from NSERC Grant No. OGPIN007.

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Cheriyan, J., Mehlhorn, K. Algorithms for dense graphs and networks on the random access computer.Algorithmica 15, 521–549 (1996). https://doi.org/10.1007/BF01940880

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