An optimal minimum spanning tree algorithm

  • Authors:
  • Seth Pettie;Vijaya Ramachandran

  • Affiliations:
  • The University of Texas at Austin, Austin, Texas;The University of Texas at Austin, Austin, Texas

  • Venue:
  • Journal of the ACM (JACM)
  • Year:
  • 2002

Quantified Score

Hi-index 0.01

Visualization

Abstract

We establish that the algorithmic complexity of the minimumspanning tree problem is equal to its decision-tree complexity.Specifically, we present a deterministic algorithm to find aminimum spanning tree of a graph with n vertices andm edges that runs in timeO(T*(m,n)) whereT* is the minimum number of edge-weightcomparisons needed to determine the solution. The algorithm isquite simple and can be implemented on a pointer machine.Althoughour time bound is optimal, the exact function describing it is notknown at present. The current best bounds known forT* are T*(m,n) =Ω(m) and T*(m,n) =O(m ∙ α(m,n)), where α is acertain natural inverse of Ackermann's function.Even under theassumption that T* is superlinear, we show thatif the input graph is selected from Gn,m,our algorithm runs in linear time with high probability, regardlessof n, m, or the permutation of edge weights. Theanalysis uses a new martingale for Gn,msimilar to the edge-exposure martingale forGn,p.