{"about":{"site":"https://codewithpapers.app","non_affiliation":"Code with Papers and Syntology are not affiliated with, endorsed by, or sponsored by Papers with Code, Meta, or the pwc-archive mirror.","licence":"CC BY-SA 4.0","licence_url":"https://creativecommons.org/licenses/by-sa/4.0/legalcode","attribution":"https://codewithpapers.app/attribution","modified":"archive material modified by Syntology; see the attribution page"},"url":"/paper/front-to-end-bidirectional-heuristic-search","title":"Front-to-End Bidirectional Heuristic Search with Near-Optimal Node Expansions","arxiv_id":"1703.03868","date":"2017-03-10","proceeding":null,"authors":["Jingwei Chen","Robert C. Holte","Sandra Zilles","Nathan R. Sturtevant"],"abstract":"It is well-known that any admissible unidirectional heuristic search\nalgorithm must expand all states whose $f$-value is smaller than the optimal\nsolution cost when using a consistent heuristic. Such states are called \"surely\nexpanded\" (s.e.). A recent study characterized s.e. pairs of states for\nbidirectional search with consistent heuristics: if a pair of states is s.e.\nthen at least one of the two states must be expanded. This paper derives a\nlower bound, VC, on the minimum number of expansions required to cover all s.e.\npairs, and present a new admissible front-to-end bidirectional heuristic search\nalgorithm, Near-Optimal Bidirectional Search (NBS), that is guaranteed to do no\nmore than 2VC expansions. We further prove that no admissible front-to-end\nalgorithm has a worst case better than 2VC. Experimental results show that NBS\ncompetes with or outperforms existing bidirectional search algorithms, and\noften outperforms A* as well.","url_abs":"http://arxiv.org/abs/1703.03868v2","url_pdf":"http://arxiv.org/pdf/1703.03868v2.pdf","source":{"archive":"pwc-archive (Hugging Face), CC BY-SA 4.0","snapshot":"2025-07-28","licence_url":"https://creativecommons.org/licenses/by-sa/4.0/legalcode","row_kind":"abstracts"},"code_links":[{"paper_slug":"front-to-end-bidirectional-heuristic-search","repo_url":"https://github.com/verbal-noun/a-star-pathfinding-family","is_official":0,"mentioned_in_paper":0,"mentioned_in_github":1,"framework":"none","reach":null}],"tasks":[{"task_slug":"heuristic-search","task_name":"Heuristic Search"}],"methods":[],"datasets_introduced":[],"methods_introduced":[],"results":[],"syntology":{"atlas_url":null,"mcp":null,"developers":"https://syntology.ai/developers"},"arxiv_metadata":null,"syntology_extracted_results":null}