The minimal set of states that must be expanded in a front-to-end bidirectional search

Eshed Shaham, Jingwei Chen, Ariel Felner, Nathan R. Sturtevant

Research output: Contribution to conferencePaperpeer-review


A* is optimal among admissible unidirectional algorithms when searching with a consistent heuristic. Recently, similar optimality bounds have been established for bidirectional search but, no practical algorithm is guaranteed to always achieve this bound. In this paper we study the nature of the number of nodes that must be expanded in any front-to-end bidirectional search. We present an efficient algorithm for computing that number and show that a theoretical parameterized generalization of MM, with the correct parameter, is the optimal front-to-end bidirectional search. We then experimentally compare various algorithms and show how far they are from optimal.

Original languageEnglish
Number of pages9
StatePublished - 1 Jan 2017
Event10th Annual Symposium on Combinatorial Search, SoCS 2017 - Pittsburgh, United States
Duration: 16 Jun 201717 Jun 2017


Conference10th Annual Symposium on Combinatorial Search, SoCS 2017
Country/TerritoryUnited States

All Science Journal Classification (ASJC) codes

  • Computer Networks and Communications

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