(This article was first published on Xi'an's Og » R, and kindly contributed to R-bloggers)
> 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 his blog: Xi'an's Og » R.
R-bloggers.com offers daily e-mail updates about R news and tutorials on topics such as: visualization (ggplot2, Boxplots, maps, animation), programming (RStudio, Sweave, LaTeX, SQL, Eclipse, git, hadoop, Web Scraping) statistics (regression, PCA, time series,ecdf, trading) and more...
Zero Inflated Models and Generalized Linear Mixed Models with R.
Zuur, Saveliev, Ieno (2012).
