On the power of structural violations in priority queues

  • Authors:
  • Amr Elmasry;Claus Jensen;Jyrki Katajainen

  • Affiliations:
  • Alexandria University, Alexandria, Egypt;University of Copenhagen, Copenhagen East, Denmark;University of Copenhagen, Copenhagen East, Denmark

  • Venue:
  • CATS '07 Proceedings of the thirteenth Australasian symposium on Theory of computing - Volume 65
  • Year:
  • 2007

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Abstract

We give a priority queue that guarantees the worst-case cost of Θ(1) per minimum finding, insertion, and decrease; and the worst-case cost of Θ(lg n) with at most lg n + O(√lg n) element comparisons per deletion. Here, n denotes the number of elements stored in the data structure prior to the operation in question, and lg n is a shorthand for max {1, log2 n}. In contrast to a run-relaxed heap, which allows heap-order violations, our priority queue relies on structural violations. By mimicking a priority queue that allows heap-order violations with one that only allows structural violations, we improve the bound on the number of element comparisons per deletion to lg n + O(lg lg n).