There is no 16-Clue Sudoku: Solving the Sudoku Minimum Number of Clues Problem · HackerPapers discussions

There is no 16-Clue Sudoku: Solving the Sudoku Minimum Number of Clues Problem — mentioned by eesmith

Fri, 12 May 2023 09:10:36 GMT

Neat! More at https://www.technologyreview.com/2012/01/06/188520/mathemati... from when it was solved 10 years ago: > 7.1 million core-hours of processing time on a machine with 640 Intel Xeon hex-core processors. They started in January 2011 and finished in December. Though the paper at https://arxiv.org/abs/1201.0749 says Sudoku solving is "only" NP-complete, so it's not really an example of "harder than NP-Complete".

Paper and discussion history. A mention is not an endorsement.

There is no 16-Clue Sudoku: Solving the Sudoku Minimum Number of Clues Problem — mentioned by triska

Mon, 10 Jun 2019 23:40:27 GMT

A valid Sudoku puzzle is such that the given clues admit precisely one solution. Hence, if you somehow manage to take into account all the initially available information, then no search is required, because, in a sense, the given hints already narrow down the entire space of (ostensibly) possible assignments to a single one. There are constraint solvers that do this. For example, with the CLP(B) version based on BDDs that I mentioned, the solver internally constructs a Binary Decision Diagram (BDD) which is like a (ideally: more compact) truth table of all assignments that satisfy the…

Paper and discussion history. A mention is not an endorsement.

There is no 16-Clue Sudoku: Solving the Sudoku Minimum Number of Clues Problem — mentioned by noname120

Mon, 10 Jun 2019 08:22:29 GMT

I believe that there is a misunderstanding regarding the role of academic publishing. Before the Internet era, the only way to make your work known to other scientists was to publish it in a journal—prestigious if possible. Journals were a medium to spread scientific information and make it available. Nowadays the situation is very much different. For example, there are preprint repositories such as arXiv where researchers can publish papers with very little oversight[1]. The journals don't serve the role of making information available anymore. Their main role is to act as a filter for…

Paper and discussion history. A mention is not an endorsement.

There is no 16-Clue Sudoku: Solving the Sudoku Minimum Number of Clues Problem — mentioned by dahart

Mon, 12 Jun 2017 18:33:51 GMT

9! * 9! is not the number of boards, that is a bad estimate. If you don't account for symmetries, rotations, re-numberings and other things, the number of boards is 6.7e21. Even if you could check a full board in a nanosecond (which you can't) enumerating that number would take more than 200,000 cpu-years. The paper linked to in the OP's article says: "Due to the sheer number of sudoku solution grids a brute force search would have been infeasible, but we found a better approach to make this project possible. Our software for exhaustively searching through a completed sudoku grid, named…

Paper and discussion history. A mention is not an endorsement.

There is no 16-Clue Sudoku: Solving the Sudoku Minimum Number of Clues Problem — HN submission

Wed, 14 Mar 2012 14:31:31 GMT

There is no 16-Clue Sudoku: Solving the Sudoku Minimum Number of Clues Problem

1 point; 0 discussion replies on HN. Paper and source history. A submission is not an endorsement.

There is no 16-Clue Sudoku: Solving the Sudoku Minimum Number of Clues Problem — HN submission

Fri, 06 Jan 2012 15:07:45 GMT

Solving the Sudoku Minimum Number of Clues Problem [pdf]

1 point; 0 discussion replies on HN. Paper and source history. A submission is not an endorsement.