Path Minima in Incremental Unrooted Trees

  • Authors:
  • Haim Kaplan;Nira Shafrir

  • Affiliations:
  • School of Computer Science, Tel Aviv University, Tel Aviv, Israel 69978;School of Computer Science, Tel Aviv University, Tel Aviv, Israel 69978

  • Venue:
  • ESA '08 Proceedings of the 16th annual European symposium on Algorithms
  • Year:
  • 2008

Quantified Score

Hi-index 0.00

Visualization

Abstract

Consider a dynamic forest of unrooted trees over a set of nvertices which we update by linkoperations: Each link operation adds a new edge adjacent to vertices in two different trees. Every edge in the forest has a weight associated with it, and at any time we want to be able to answer a path-minquery which returns that edge of minimum weight along the path between two given vertices.For the case where the weights are integers we give an algorithm that performs n茂戮驴 1 link operations and mpathmin queries in O(n+ m茂戮驴(m,n)) time. This extends well known results of Tarjan [11] and Yao [12] to a more general dynamic setting at the cost of restricting the weights to be integers. We also suggest a simpler data structures for the case where trees are rooted and the link operation always adds an edge between the root of one tree and an arbitrary vertex of another tree.