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

arXiv: https://arxiv.org/abs/1401.4597 · HTML: https://mlsanity.com/paper/1401.4597/

## Key facts

- Cited by 8 papers in the map (data through 14 Oct 2026).
- First posted on arXiv 18 Jan 2014.

## Built on by (most cited first, 8 of 8)

- [Evaluating Human-Language Model Interaction](https://mlsanity.com/paper/2212.09746/) (2022)
- [Decrypting Cryptic Crosswords: Semantically Complex Wordplay Puzzles as a Target for NLP](https://mlsanity.com/paper/2104.08620/) (2021)
- [Automated Crossword Solving](https://mlsanity.com/paper/2205.09665/) (2022)
- [Clue-Instruct: Text-Based Clue Generation for Educational Crossword Puzzles](https://mlsanity.com/paper/2404.06186/) (2024)
- [Language Models are Crossword Solvers](https://mlsanity.com/paper/2406.09043/) (2024)
- [Down and Across: Introducing Crossword-Solving as a New NLP Benchmark](https://mlsanity.com/paper/2205.10442/) (2022)
- [Constraint Satisfaction Approaches to Wordle: Novel Heuristics and Cross-Lexicon Validation](https://mlsanity.com/paper/2510.02855/) (2025)
- [The WebCrow French Crossword Solver](https://mlsanity.com/paper/2311.15626/) (2023)

## Abstract (arXiv)

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.Fillls performance on crosswords from the American Crossword Puzzle Tournament suggests that it ranks among the top fifty or so crossword solvers in the world.