Note: A simple and efficient Union-Find-Delete algorithm

  • Authors:
  • Amir Ben-Amram;Simon Yoffe

  • Affiliations:
  • -;-

  • Venue:
  • Theoretical Computer Science
  • Year:
  • 2011

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Abstract

The Union-Find data structure for maintaining disjoint sets is one of the best known and widespread data structures, in particular the version with constant-time Union and efficient Find. Recently, the question of how to handle deletions from the structure in an efficient manner has been taken up, first by Kaplan et al. (2002) [2] and subsequently by Alstrup et al. (2005) [1]. The latter work shows that it is possible to implement deletions in constant time, without affecting adversely the asymptotic complexity of other operations, even when this complexity is calculated as a function of the current size of the set. In this note we present a conceptual and technical simplification of the algorithm, which has the same theoretical efficiency, and is probably more attractive in practice.