20 Mar
2007
20 Mar
'07
11:08 a.m.
Ivan Miljenovic wrote:
(a primitive Sudoku solver, to be precise)
Concerning Sudoku, there is a beautiful talk from R. Bird http://icfp06.cs.uchicago.edu/bird-talk.pdf
The other problem with using a list of lists is that the only reason I'm sure that the matrix is valid (i.e. all the rows are the same length, etc.) is because I created it that way, not because the data structure requires it.
You can use nested data types in order to ensure squareness, see also C. Okasaki. From Fast Exponentiation to Square Matrices: An Adventure in Types http://www.eecs.usma.edu/webs/people/okasaki/pubs.html#icfp99 Regards, apfelmus