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| Thanks to feedback I've now added a sanity check when you enter numbers. If there is a conflict - ie the same number in a row, column or box - it will hightlight those squares in red. You'll notice this especially if your choices are wrong and you continue to 'take steps'. Also in this version is an email button. You can send a link to a friend containing the current board. Note: This is the board *as it looks now* - so you can send completed boards or new boards, whatever is currently shown. New in version 1.06 We now have a back button. Look for the [<<] button next to Take Step. Goes back one step. New in version 1.07 Added Remote Pairs test. New in version 1.08 Some extra checks including pointing pairs and pointing triples. Thanks to Phil Jackson for help with these. New in version 1.09 A new test/strategy called Box/Line Reduction. Thanks to Andrew Pepperdine for this one. New in version 1.10 Jethro Foreman, from Walton on Thames, has helped me enhance my first pairs test. This eliminates superfluous possibles from squares where pairs are hidden. Before I was only removing possibles from other squares in a box where open pairs were found. Confused? There'll be a explanation page soon. Just nice to know that after two weeks we're still finding better strategies. New in version 1.11 (June 28th) The remote pairs test has been taken a step further and is more generalised. A number of peripheral features have been added and enhanced including the Printable Version. New in version 1.13 (July 28th) Don't know what happened to 1.12, but 1.13 now includes a version of the X-Wing strategy and the Sword Fish strategy. I'm calling them the basic version because I'm looking at rows and columns only. Box versions to come, but these are a powerful tests. I've also changed the looping strategy to cope with having all these tests. There can be nasty conflicts if they are run in sucession without chearing up the board first. New in version 1.14 (August 12th) I have broken up the trivial tests to seperate showing possibles from checking for single candidates. This makes it clearer which rule has been used and will help people understand the steps being taken. New in version 1.15 (August 23rd) Thank-you to Joris S.de Wit of the Netherlands for finding an example which one of the pairs tests didn't catch. To do with those awkward boxes. Well done Joris! Also, Flemming Birkbak of Denmark writes in with a hidden pair I'd not seen before. Big thanks to him also. August 26rd - I have replaced the example list of Sudoku's with a set of my own from my own generator. There are some normal ones - graded - and some freaks. The two Extreme ones are the worst (highest scoring) of a batch of 33,000. See how you like them. Try them without using the solver first! I dare you. New in version 1.16 (September 4th) The swordfish algorithm is now much better, thanks to prompting by Ron Cowpe of Canada who provided a good example. It needed a good re-write as well since it was too slow. I've not found an example SwordFish that it can't detect. Hopefully! New in version 1.17 (September 20th) I've split out the triples test from the main pairs tests so its easier to spot. Triples occur in the same row, column or box where you have, for example, 1/5 1/5/8 and 1/8 in three cells. 1,5 and 8 can be removed from any of the remaining 5 cells. New in version 1.18 (November 7th) Hidden Triples added. Nasty little beast. Big thanks to Matt Rivers from Northridge, California for sending in a board with a perfect example. Now added to the documentation. Since this goes hand in hand with Hidden Pairs (but is much more complicatied as it requires three numbers not just in threes but say 3/2/2 or 3/3/2). I've put the hidden pairs/triples test on its own. That means combining the naked pairs/triples tests which go together logically. New in version 1.19 (December 20th) Y-Wings have been added to the strategy list. Documentation added here. New in version 1.20 (December 23th) Thanks to Tim van Kampen for a very fiendish Sudoku, I've extended Hidden Pairs/Triples to Hidden Quads. Same principle, just four numbers spaced in four cells across a row, column or box. New in version 1.21 (January 11th) Added the Import Sudoku button. New in version 1.22 (February 24th) Major update. Apart from adding the excellent strategy Aligned Pair Exclusion I've added a report box which gives you all the moves when a strategy executes. Lots of requests for this. Some minor bug fixes as well. New in version 1.23 (April 22nd) Prompted by Mike Blake and some of his javacode I've added Type 1 Unique Rectangles. Note: this strategy assumes the Sudoku has a single unique solution. If the answer goes awry then it may not be. New in version 1.24 (May 1st) Naked Quads added by demand. New in version 1.25 (May 3rd) You can now edit the numbers in the large sudoku board and enter more than one number to make changes to the 'notes' or candidates. This will reset the solving stage back to the start (so knock on effects are taken into account). New in version 1.26 (May 23rd) Many people have written to me to comment about multiple solutions for a given Sudoku. There are no logical tricks the solver can use to detect this other than not complete correctly. The only way to check this is to perform a brute force analysis which tests every possible legal placement of a number. Computers are good at this and we now have a new yellow button called "Solution Count". Try this on any Sudoku to check if it has a unique solution. New in version 1.27 (May 28th) Had some queries about the Extended APE not working. Actually it wasn't included in the solver but that's now changed. All the EAPE examples with work. Because I moved the Y-Wing before APE the normal APE the Y-Wing gets the result first. I'll upload an APE that can't be done with Y-Wing soon. New in version 1.28 (May 29th) Designed a much faster Sword-Fish detection allgorith. Also fixed a bug introduced in 1.27 when APE was extended. New in version 1.30 (July 7th 2006) Version 1.30 is a major update since I've found a way to include all the advanced strategies in my off-line C++ solver that were simply not possible to program in Javascript. Much still remains in javascript but its mostly user interface stuff now. New in version 1.31 (July 13th 2006) Minor update. Certain formations were not being detected for Type 4/4B Unique Rectangles. Added Hidden Unique Rectangles. Split out AICs with and without grouped nodes. New in version 1.32 (July 22th 2006) Two new Extreme strategies added: Sue-de-Coq and Two Disjoint Almost Locked Sets. New in version 1.33 (Ausgut 24th 2006) Fixed the back button bug, added strategy toggle checkboxes. New in version 1.34 (August 29th 2006) Changed AIC strategies to return the shorest chain result. New in version 1.35 (September 9th 2006) Save button now saves permanently (using a cookie) even if you browse away or close your browser. New in version 1.36 (September 16th 2006) Added Multivalue X-Wing strategy and extended the scope of Almost Locked Sets. New in version 1.37 (September 30th 2006) Added Death Blossom by Mike Barker. New in version 1.38 (November 21st 2006) New Jigsaw Solver released! New in version 1.39 (December 2nd 2006) Much faster Advanced Strategies - the solver now continues to search for the first strategy that returns a result (applies to X-Wings and beyond). This will save you a lot of time clicking and ease the server load as well. New in version 1.40 (March 21st 2007) New variation of the Hidden Unique Rectangle has been added. Thanks to Mage in France for giving me an excellent example. New in version 1.50 (May 25th 2008) I have added a grading button to this solver. Many people have asked for a grade check to see if their puzzles are accurately graded. Note that different publishers will have very different methods of grading, some good, some poor. For more information on my grading I have a paper on this topic. Detection of X-Cycles has been improved, thanks to Thomas Kimble for the examples. Other minor accumulated improvements as well. New in version 1.51 (Feb 1st 2009) Split out Hidden Unique Rectangles from Unique Rectangles to make it more visible and to provide a link to the strategy from the solver page. |
| New in version 1.52 (March 1st 2009) Save and Reload cookie now remembers candidates. New in version 1.53 (Apr 14th 2009) Code consolidation and minor bug fixes. New in version 1.60 (June 13th 2009) Killer Sudoku Solver released; new method implemented for client-server comms. New in version 1.62 (Jan 25th 2010) Chaining strategies that report chains now display those chains as a new graphical element on the big board. |
