Dynamically improved bounds bidirectional search

Abstract

This paper presents a bidirectional search algorithm that dynamically improves the bounds during its execution. It has the property that it always terminates on or before the forward search meets the backward search. Computational experiments on the pancake problem, the sliding tile puzzle, and the topspin problem demonstrate that it is capable of solving problems using significantly fewer node expansions than A⁎ or state-of-the-art bidirectional algorithms such as MMϵ and GBFHS.