A priority queue with the time-finger property

  • Authors:

  • Amr Elmasry;Arash Farzan;John Iacono

  • Affiliations:

  • Computer Science Department, University of Copenhagen, Denmark;Max-Planck-Institut für Informatik, Saarbrücken, Germany;Polytechnic Institute of New York University, Brooklyn, New York, USA

  • Venue:
  • Journal of Discrete Algorithms
  • Year:
  • 2012

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Abstract

We present a priority queue that supports insert in worst-case constant time, and delete-min, access-min, delete, and decrease of an element x in worst-case O(log(min{w"x,q"x})) time, where w"x (respectively, q"x) is the number of elements that were accessed after (respectively, before) the last access to x and are still in the priority queue at the time when the corresponding operation is performed. (An access to an element is accounted for by any priority-queue operation that involves this element.) Our priority queue then has both the working-set and the queueish properties; and, more strongly, it satisfies these properties in the worst-case sense. From the results in Iacono (2001) [11] and Elmasry et al. (2011) [7], our priority queue also satisfies the static-finger, static-optimality, and unified bounds. Moreover, we modify our priority queue to realize a new unifying property - the time-finger property - which encapsulates both the working-set and the queueish properties.