Hajime wrote:I can confirm that all 20 JSB layouts have a solution
Ok, great!
PM me with an email address and I'll send you more ... 2500 JS-only and 2500 JSB, say?
Hajime wrote:I can confirm that all 20 JSB layouts have a solution
Mathimagics wrote: ... 2500 JS-only and 2500 JSB, say?
Mathimagics wrote:Done ...
222111333422211333442211353444211553444666555866667559868767959888777999888777999
333395555313196565311196665311196665321297675422297778422297778442498788444498888
....6.....3.....8...6...4.....2.6...9...8...7...4.5.....7...1...5.....2.....1.... 112222233111112333114422253644775553647777753644477553648885599666899999668888899
...8.3....3..2..8...6.5.4............23...65............7.3.1...5..4..2....9.8... 112222233111112333114422253644775553647777753644477553648885599666899999668888899
Analysis results
Difficulty rating: 6,6
This Sudoku Jigsaw can be solved using the following logical methods:
58 x Hidden Single
2 x Direct Pointing
1 x Direct Claiming
6 x Cage Pointing
1 x Claiming
1 x Generalized Intersection
1 x X-Wing
2 x Generalized X-Wing
1 x Turbot Fish
111223333111222233141222333145555666444456666444555567888999767889999777888899777
111223333111222233141222333144455666445555566444556667888999767889999777888899777
111223333112222334111255334166255344666257444668557449688557999688777799888877999
Hajime wrote:Shall I add these JS layouts to the 2500 selections of SiSeSuSo?
Mathimagics wrote:Just to give a little example of the problem, here are two JL's, both of which are invalid:Two invalid JLs: Show
The left-hand JL must be invalid because it requires the cells marked "A" to have the same value, and consequently the region below, which is entirely contained in cols 8 and 9, has nowhere that A can go.
But what about the other JL? Is there a simple logical argument one can make to demonstrate its invalidity? Can the "Law of Leftovers" tell us that this JL is invalid? I very much doubt that, but would be very happy to be proven wrong, so by all means have a go at it.
Mathimagics wrote:
You might like to think about ways to use software to confirm this. Is there any free solver that can do this? JSudoku as far as I can tell is the only one that has inboard general Jigsaw support. One should approach this with caution, however - I am currently testing this JL in JSudoku, by filling in the first region as givens, and then recursively solving. This has been running for over 32 hours (!) so far without any resolution!
I do have a method which is generic (requires no pattern analysis, "advanced solving techniques", etc), and in this case identifies the JL as invalid in less than 100ms. I will describe this method shortly, but I must point out here that some invalid-JL cases can take much longer, up to 5 minutes.
Anyway, if you have solvers that can be used to attack the problem by any other means, we would definitely like to hear about it.
sigh wrote:... valid jigsaw layouts, especially the the more difficut ones? Would I be able to get a copy?
sigh wrote:My brute-force solver helped me find a simple proof that the second layout is invalid ...