PACE Solver Description: Bute-Plus: A Bottom-Up Exact Solver for Treedepth

Author James Trimble

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James Trimble
  • School of Computing Science, University of Glasgow, Scotland, UK


I would like to thank the PACE 2020 program committee and the team for a well-organised and enjoyable contest.

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James Trimble. PACE Solver Description: Bute-Plus: A Bottom-Up Exact Solver for Treedepth. In 15th International Symposium on Parameterized and Exact Computation (IPEC 2020). Leibniz International Proceedings in Informatics (LIPIcs), Volume 180, pp. 34:1-34:4, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2020)


This note introduces Bute-Plus, an exact solver for the treedepth problem. The core of the solver is a positive-instance driven dynamic program that constructs an elimination tree of minimum depth in a bottom-up fashion. Three features greatly improve the algorithm’s run time. The first of these is a specialised trie data structure. The second is a domination rule. The third is a heuristic presolve step can quickly find a treedepth decomposition of optimal depth for many instances.

Subject Classification

ACM Subject Classification
  • Theory of computation → Graph algorithms analysis
  • Theory of computation → Algorithm design techniques
  • Treedepth
  • Elimination Tree
  • Graph Algorithms


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