A*+BFHS: A Hybrid Heuristic Search Algorithm

We present a new algorithm called A*+BFHS for solving problems with unit-cost operators where A* and IDA* fail due to memory limitations and/or the existence of many distinct paths between same pair nodes. is based on breadth-first heuristic search (BFHS). combines advantages from both algorithms, namely A*'s node ordering, BFHS's savings, algorithms' duplicate detection. On easy problems, behaves as A*. hard it slower than but saves large amount memory. Compared BFIDA*, reduces time requirement by several times variety planning domains.