Dr.Fill: Crosswords and an Implemented Solver for Singly Weighted CSPs

We describe Dr. Fill, a program that solves American-style crossword puzzles. From a technical perspective, Dr. Fill works by converting crosswords to weighted csps, and then using a variety of novel techniques to find a solution. These techniques include generally applicable heuristics for variable and value selection, a variant of limited discrepancy search, and postprocessing and partitioning ideas. Branch and bound is not used, as it was incompatible with postprocessing and was determined experimentally to be of little practical value. Dr. Fill's performance on crosswords from the American Crossword Puzzle Tournament suggests that it ranks among the top fifty or so crossword solvers in the world.

[1]  W. D. Harvey,et al.  Nonsystematic backtracking search , 1995 .

[2]  Simon de Givry,et al.  Existential arc consistency: Getting closer to full arc consistency in weighted CSPs , 2005, IJCAI.

[3]  Hinrich Schütze,et al.  Book Reviews: Foundations of Statistical Natural Language Processing , 1999, CL.

[4]  D. Sontag.  1 Introduction to Dual Decomposition for Inference , 2010 .

[5]  Simon de Givry,et al.  Mendelian Error Detection in Complex Pedigrees Using Weighted Constraint Satisfaction Techniques , 2007, Constraints.

[6]  Martin C. Cooper,et al.  Soft arc consistency revisited , 2010, Artif. Intell..

[7]  Jennifer Chu-Carroll,et al.  Building Watson: An Overview of the DeepQA Project , 2010, AI Mag..

[8]  Javier Larrosa,et al.  On the Dual Representation of Non-binary Semiring-based CSPs , 2000 .

[9]  Jonathan Schaeffer,et al.  Man versus Machine for the World Checkers Championship , 1993, J. Int. Comput. Games Assoc..

[10]  Thomas Schiex,et al.  Solving weighted CSP by maintaining arc consistency , 2004, Artif. Intell..

[11]  Richard E. Korf,et al.  Improved Limited Discrepancy Search , 1996, AAAI/IAAI, Vol. 1.

[12]  George A. Miller,et al.  WordNet: A Lexical Database for English , 1995, HLT.

[13]  David Joslin,et al.  "Squeaky Wheel" Optimization , 1998, AAAI/IAAI.

[14]  Rina Dechter,et al.  AND/OR Branch-and-Bound search for combinatorial optimization in graphical models , 2009, Artif. Intell..

[15]  Michael J. Quinn,et al.  Taking Advantage of Stable Sets of Variables in Constraint Satisfaction Problems , 1985, IJCAI.

[16]  Simon de Givry,et al.  Bounds Arc Consistency for Weighted CSPs , 2009, J. Artif. Intell. Res..

[17]  Thomas Schiex,et al.  Semiring-Based CSPs and Valued CSPs: Frameworks, Properties, and Comparison , 1999, Constraints.

[18]  Murray Campbell,et al.  Deep Blue , 2002, Artif. Intell..

[19]  Michael L. Littman,et al.  A probabilistic approach to solving crossword puzzles , 2002, Artif. Intell..

[20]  Boi Faltings,et al.  Open constraint programming , 2005, Artif. Intell..

[21]  Matthew L. Ginsberg,et al.  GIB: Steps Toward an Expert-Level Bridge-Playing Program , 1999, IJCAI.

[22]  Marco Gori,et al.  WebCrow: A Web-Based System for Crossword Solving , 2005, AAAI.

[23]  李幼升,et al.  Ph , 1989 .

[24]  Jon Doyle,et al.  A Truth Maintenance System , 1979, Artif. Intell..

[25]  Michael C. Frank,et al.  Search Lessons Learned from Crossword Puzzles , 1990, AAAI.

[26]  Tommi S. Jaakkola,et al.  Introduction to dual composition for inference , 2011 .

[27]  Alan K. Mackworth.  Consistency in Networks of Relations , 1977, Artif. Intell..

[28]  David A. McAllester.  Partial Order Backtracking , 1993 .

[29]  Matthew L. Ginsberg,et al.  Limited Discrepancy Search , 1995, IJCAI.

[30]  Lakhdar Sais,et al.  Reasoning from last conflict(s) in constraint programming , 2009, Artif. Intell..

[31]  Lakhdar Sais,et al.  Boosting Systematic Search by Weighting Constraints , 2004, ECAI.

[32]  Dana S. Nau,et al.  Total-Order Multi-Agent Task-Network Planning for Contract Bridge , 1996, AAAI/IAAI, Vol. 1.

[33]  Christiane Fellbaum,et al.  Book Reviews: WordNet: An Electronic Lexical Database , 1999, CL.