No help from here on the difficulty calculation for Sudoku solving. My solver works like most of them, I'd guess. From the starting position:
1) Add any "must have" numbers, if any, to the set of known square values. 2) Delete any "can't be" numbers from the list of possible numbers for each square. 3) After any update to the known square values, and when the possibles have been completely updated on one run-through - run #1 and #2 again, to "propagate" the changes all the way across the board, as far as they can go. 4) Run the board through the "laws of pairs (inside and or outside), to further help find the solution. The above solves all the easy and medium difficulty boards, in almost no time. The most difficult boards will have to involve some guessing. Start with the squares which have the fewest possible's left for their square: 2 possibles, then a square with 3 possibles, etc. This is simply intelligent trial and error. On your site, the board looks great for the starting position, but the answer board looks crummy. (doesn't even look like a Sudoku puzzle board). I'd put the answer squares right up into the starting board, or a board just like it. When I selected "one step" and clicked on "solve", nothing happened, despite several clicks. When a puzzle has more than one solution, your solver should solve it anyway, and not put zero's into a square. This is a solver, not a tester for originality which fails to give any solution, when more than one solution, exists. Lots of problems have more than one solution. There is a problem set of Sudoku puzzles that have just one answer, but have very few square values given for the start - only 17 sqrs. I believe. VERY difficult. If your solver can solve all of them, in a short amount of time, you really have a great solver. Don't recall the url for the most difficult one solution puzzles, but Google was my guide when I stumbled on it, quite by accident. Those "buttons" were well below what anyone would expect to see, today. A beautiful puzzle like Sudoku deserves a beautiful gui interface. On Dec 31 2007, 4:38 am, Deeþan Chakravarthy <[EMAIL PROTECTED]> wrote: > Hi Guys, > I am wondering if you guys have any idea on algorithm used for solving > Sudoku puzzles. In particular if you guys know about any method to > calculate the difficulty level of a given sudoku it will be great. I do > understand that the number of filled in cells alone is not a measure of > the difficulty level of a puzzle. Here is my online solver for sudoku. > Please try it and pass feedback on the same. > > http://sudoku-solver.net > > Regards > Deepan --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Algorithm Geeks" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/algogeeks -~----------~----~----~----~------~----~------~--~---
