fast sudoku app, now on the appengine!

[alexr_rwx]

Been working on this off and on for a few months, but here it is! http://sudokudlx.appspot.com/

It's not that sudoku is particularly earth-shattering (is it still popular?) -- I wrote a fairly naive solver for it a few years ago. What's interesting about this is Knuth's extremely metal constraint-satisfaction algorithm, Dancing Links. It's very, very fast. And I think this implementation of it is clean enough to be reusable, maybe even for other people!

Over on that other blog, there will be a more thorough treatment about the algorithm, how to implement it, and how to apply it to sudoku, probably in a day or two.

Comments

[rheavatarin.livejournal.com]

Solving sudoku, while interesting on a theoretical level, doesn't help me with my boredom! Surely you could write an app that generates puzzles.

[oniugnip.livejournal.com]

Ooh! That's a good idea. I can do that :)

I may not have ever solved a whole sudoku by hand -- any thoughts on what makes a given puzzle more or less fun?

[rheavatarin.livejournal.com]

I suggest you solve a couple because it is difficult to explain. There are basically two levels of play to look at. I find that the most interesting puzzles are ones that require very few guesses to solve, but are still challenging. I've not done any research into how exactly that is done, but I'm positive that someone has considering the proliferation of sudoku books and that somehow difficulty ratings for puzzles are obtained.

[billings.livejournal.com]

"Fun" is "hard, but not too hard." So it's really more about evaluating difficulty, I'd think.

[deepdistraction.livejournal.com]

All I know is that sudoku suddenly seems less fun now that the solution is so easily obtained.

[lindseykuper]

What I think is truly funny is that Alex has never actually done a sudoku puzzle. He just writes sudoku solvers!

[(Anonymous)]

how is it that you are so darn smart?
-LBrewer

[oniugnip.livejournal.com]

Good genes and clean livin'.