Site icon R-bloggers

Surprising sudoku

[This article was first published on Xi'an's Og » R, and kindly contributed to R-bloggers]. (You can report issue about the content on this page here)
Want to share your content on R-bloggers? click here if you have a blog, or here if you don't.
> printSudoku(z)
 +-------+-------+-------+
 |   9   |       | 7   5 |
 |     6 |       |   9   |
 | 4 5 3 | 1 7   | 2 8   |
 +-------+-------+-------+
 |     5 |     7 |   6   |
 | 1   9 | 6 8   |       |
 |   8   |   3   |     1 |
 +-------+-------+-------+
 | 7   2 | 5 9   | 4     |
 |       |     2 | 6 7   |
 |       |   6   |     2 |
 +-------+-------+-------+

Yesterday, I was finishing a sudoku grid in the metro and I ended up with four entries a,b,b,a that could be entered in two symmetric ways! Nothing mathematically surprising. However, this never happened to me before and, while it is obviously a possibility, I had not realised that sudoku creators could choose this option… This is not a well-defined question, but how likely is it that one ends up with such an exchange quadruplet (or rather pair of pairs)?! (The above was written using the sudoku R solver, pointed out there.)


Filed under: R, Statistics Tagged: R, sudoku

To leave a comment for the author, please follow the link and comment on their blog: Xi'an's Og » R.

R-bloggers.com offers daily e-mail updates about R news and tutorials about learning R and many other topics. Click here if you're looking to post or find an R/data-science job.
Want to share your content on R-bloggers? click here if you have a blog, or here if you don't.