Where to find extreme(+) puzzles?

Everything about Sudoku that doesn't fit in one of the other sections

Re: Where to find extreme(+) puzzles?

Postby SpAce » Tue Sep 26, 2017 4:24 am

I said above that I like to take the path of least resistance, but I guess it's a relative term. On second thought, I may need to make some adjustments even if they're not absolutely necessary for solving success. For example:

Last weekend I solved another Nightmare (Feb 3, 2008) which turned out to be the most difficult (7.9) of them I've encountered so far: 040000030200503004007000600030409050000010000090205040008000400500706008070000090. Still, I guess it wasn't nearly as difficult as my solve path would suggest.

My solution used 18 chains and nets, some of which were pretty complicated. I did enjoy hunting them, but it's hard to justify the complexity if I look at the Hoduko solution which used only 9 chains, none of which were very complicated.

I suspect my biggest leak was that I skipped fishing as always. Seems that I need to start paying attention to that if I want to simplify my solve paths. There are other leaks, of course, but that seems the most obvious and perhaps easiest to fix first.
Code: Select all
   *             |    |               |    |    *
        *        |=()=|    /  _  \    |=()=|               *
            *    |    |   |-=( )=-|   |    |      *
     *                     \  ¯  /                   *   
SpAce
 
Posts: 605
Joined: 22 May 2017

Re: Where to find extreme(+) puzzles?

Postby StrmCkr » Tue Sep 26, 2017 5:07 am

What are those? I can find information about M-wings and L-wings you also mentioned but not those two.


in essence A.I.C / discontinuous/continuous Nice loops of 3/4 strong=weak links between 1-2 digits are classed and defined and finally named:

this post contains direct links for the other types i mentioned]

S-wing

the H-wing is used by a few people on here an a few other different forums and first appeared and was joking dubbed as a "purple cow" for us long timer :) {which is still displayed as such in xsudoku! }

    Hybrid wings. {pattern defined but no developed thread with examples as it has way to many to display them all. }

    H2-Wing: (X=Y)a - (Y)b = (Y-Z)c = (Z)d "a" and "d" in same unit; a<>Z, d<>X
    H3-Wing: (X=Y)a - (Y=Z)b - (Z)c = (Z)d "a" and "d" in same unit; a<>Z, d<>X


Code: Select all
.-----------------.-------------------.---------------------.
| 1689  4    1569 | 1689  26789  1278 | 125789  3     12579 |
| 2     168  169  | 5     6789   3    | 1789    178   4     |
| 3     158  7    | 189   2489   1248 | 6       128   1259  |
:-----------------+-------------------+---------------------:
| 1678  3    126  | 4     678    9    | 1278    5     1267  |
| 4678  568  2456 | 368   1      78   | 2789    2678  23679 |
| 1678  9    16   | 2     3678   5    | 178     4     1367  |
:-----------------+-------------------+---------------------:
| 169   126  8    | 139   2359   12   | 4       1267  12567 |
| 5     12   49   | 7     49     6    | 3       12    8     |
| 146   7    3    | 18    2458   1248 | 125     9     1256  |
'-----------------'-------------------'---------------------'

basics to this point then:
Almost Locked Set XY-Wing: A=r3c24568 {124589}, B=r8c5 {49}, C=r1268c3 {14569}, X,Y=4,5, Z=9 => r12c5<>9
W-Wing: 1/2 in r7c6,r8c8 connected by 2 in r78c2 => r7c89<>1
Finned Swordfish: 8 r146 c157 fr1c4 fr1c6 => r23c5<>8
Locked Candidates Type 1 (Pointing): 6 in b1 => r2c5<>6
followed by easy steps brings it to here:
Code: Select all
.----------------.-----------------.-------------------.
| 189   4    159 | 6    28    128  | 12579  3    12579 |
| 2     168  169 | 5    7     3    | 19     18   4     |
| 3     158  7   | 189  249   1248 | 6      128  125   |
:----------------+-----------------+-------------------:
| 1678  3    126 | 4    68    9    | 1278   5    127   |
| 48    58   245 | 38   1     7    | 289    6    239   |
| 1678  9    16  | 2    368   5    | 178    4    137   |
:----------------+-----------------+-------------------:
| 169   126  8   | 139  2359  12   | 4      7    256   |
| 5     12   49  | 7    49    6    | 3      12   8     |
| 146   7    3   | 18   2458  1248 | 125    9    1256  |
'----------------'-----------------'-------------------'

Almost Locked Set XY-Wing: A=r1c156 {1289}, B=r23c8,r3c9 {1258}, C=r7c1269 {12569}, X,Y=5,9, Z=1,2 => r1c79<>1, r1c79,r3c56<>2
Almost Locked Set XY-Wing: A=r2c238 {1689}, B=r126c3 {1569}, C=r1c79,r2c7 {1579}, X,Y=1,5, Z=9 => r1c1,r8c3<>9
more basic steps:
Code: Select all
.---------------.-------------.--------------.
| 18    4   59  | 6   2    18 | 579   3  579 |
| 2     16  169 | 5   7    3  | 19    8  4   |
| 3     58  7   | 9   4    18 | 6     2  15  |
:---------------+-------------+--------------:
| 1678  3   126 | 4   68   9  | 1278  5  127 |
| 4     58  25  | 38  1    7  | 289   6  239 |
| 1678  9   16  | 2   368  5  | 178   4  137 |
:---------------+-------------+--------------:
| 9     16  8   | 13  35   2  | 4     7  56  |
| 5     2   4   | 7   9    6  | 3     1  8   |
| 16    7   3   | 18  58   4  | 25    9  256 |
'---------------'-------------'--------------'

Almost Locked Set XZ-Rule: A=r1246c3 {12569}, B=r12456c7 {125789}, X=5, Z=2 => r4c9<>2
Almost Locked Set XZ-Rule: A=r15c3 {259}, B=r134679c9 {1235679}, X=9, Z=2 => r5c9<>2

singles to the end.
Some do, some teach, the rest look it up.
User avatar
StrmCkr
 
Posts: 862
Joined: 05 September 2006

Re: Where to find extreme(+) puzzles?

Postby ghfick » Tue Sep 26, 2017 12:23 pm

champagne wrote:
Here, we have an heavily downgraded form of potential exocet for the base r12c9 target r6c7 r7c8

1 in the base => 1r7c8
5 in the base => 5r6c7

if you can prove that 4 in the base => 4 (r6c7,r7c8) you have an exocet.

Junior exocet in the most common pattern to prove it and is there in most cases.
In other cases "classical AICs" can establish it


Using the [hidden] UR : r16c79 with {4,5} we see that r6c7 <> 4. So to have an exocet here, we would need to prove that 4 in the base => 4r7c8. Alas, there does not appear to be such a proof.
Can you suggest [or point to] a tough puzzle that contains a 'real' exocet that is not Junior?
David P Bird's compendium contains a section on the 'Senior Exocet'. You are suggesting a different type of extension where the base cells and target cells are in the same band but the 'S' cell requirement is not met.
The use of AICs in this situation suggests some commonalities with Krakens.
ghfick
 
Posts: 37
Joined: 06 April 2016

Re: Where to find extreme(+) puzzles?

Postby David P Bird » Tue Sep 26, 2017 4:45 pm

GF the 'Senior Exocet' variation described in the compendium allows target cells to be outside the base cell band. It can just about be classed as a recognisable pattern as it consists of a defninite number of elements that can be checked without needing to track chains. But Champagne's base cells and targets are all in the same band so it does not apply.

As Champagne is willing to accept inference tracking using chains or nets as a means of proving that a pattern exists, he has greater freedom to confirm the pattern is an Exocet.

Champagne, I hope that this contribution makes your life easier as it should save you from having to either read for the first time or revise the defintion of a Senior Exocet!

David
.
David P Bird
2010 Supporter
 
Posts: 1040
Joined: 16 September 2008
Location: Middle England

Re: Where to find extreme(+) puzzles?

Postby SpAce » Mon Oct 02, 2017 10:34 pm

Thanks for the info, StrmCkr!
Code: Select all
   *             |    |               |    |    *
        *        |=()=|    /  _  \    |=()=|               *
            *    |    |   |-=( )=-|   |    |      *
     *                     \  ¯  /                   *   
SpAce
 
Posts: 605
Joined: 22 May 2017

Re: Where to find extreme(+) puzzles?

Postby SpAce » Thu Mar 22, 2018 11:28 am

Back to where I started. I finally decided to face my original nemesis a third time and see if I'd learned anything in half a year. As told above, my very first attempt on that particular SE 8.4 puzzle failed miserably. As also told, my second attempt sort of solved it, but I wasn't at all happy about how it happened, so I never really counted it. It's been bugging me a bit, but I never looked at the puzzle again until now. Here's what I came up with (unedited p&p steps):

1. AIC (AHS): (6)r3c1 = r3c4 - r1c5 = (6-4)r4c5 = r8c5 - r7c4 = (41-6)r7c89 = (6)r8c9 => -6 r8c1
2. AIC-Loop (ANS, Grouped): (2)r8c4 = (2-4)r7c4 = r7c89 - (4=[9]2)r8c78 - loop => -35 r7c4, -2 r8c1; -9 r8c16, r7c89, r9c79
3. AIC: (2=7)r9c7 - (7=9)r3c7 - r8c7 = (9)r8c8 => -2 r8c8
4. AIC-Hydra (ANS): (#2)r4c8 = r7c8 - (2=94)r8c78 - (4)r8c5 = (#4-1|6)r4c5 = (61)r12c5 - (1=5)r2c9 - r6c9 = (#5)r6c7 => -4 r4c8, -2 r6c7
5. AIC-Hydra (AHS): (#5)r8c6 = (5-#2)r8c4 = (2-4)r7c4 = (41-3)r7c89 = r9c9 - (3=#8)r9c5 => -8 r8c46
6. AIC-Loop (Grouped): (8)r6c3 = r9c3 - (8=3)r8c8 - r79c3 = (3)r6c3 - loop => -2 r6c3; -3 r7c12, r9c2
7. AIC-Hydra: (#8)r4c4 = r6c4 - r6c3 = r9c3 - r9c5 = (8-4)r8c5 = (#4-6)r4c5 = r1c5 - (6=#3)r3c4 => -34 r4c4
8. Kite: (6)r3c1 = r3c4 - r1c5 = (6)r4c5 => -6 r4c1
9. AIC (ANS): (5=1)r2c9 - r2c5 = (1-6)r1c5 = (6-4)r4c5 = r8c5 - (4=92)r8c78 - (2=7)r9c7 - r9c9 = (7)r6c9 => -5 r6c9
10. Kraken Cell: (1378)r1c4 => -26 r1c2 (*a)
11. AIC: (7)r3c8 = r3c7 - (7=2)r9c7 - r7c8 = (2)r4c8 => -7 r4c8
12. Kraken Cell (Nested, ANS): (157)r5c6 => -7 r5c8 (*b)
13. AIC: (2=6)r1c3 - r1c5 = (6-4)r4c5 = r8c5 - (4=2)r7c4 => -2 r7c3
14. Kraken Cell (Grouped): (3467)r4c2 => +8 r6c3 (*c)
15. AIC: (6)r5c4 = r4c5 - (6=1)r1c5 - r1c7 = r4c7 - (1=4)r5c8 => -4 r5c4
16. AIC: (3)r2c5 = (3-6)r3c4 = (6-5)r5c4 = r8c4 - (5=3)r8c6 => -3 r8c5
17. Skyscraper: (6)r1c3 = r5c3 - r5c4 = (6)r3c4 => -6 r3c1, r1c5; stte

Details for (*a, *b, *c):
Hidden Text: Show
(*a)
Code: Select all
r1c4:
|(7)-r1c1==============(7)r1c2--|-(26)r1c2
|(1)-r4c7=r1c7-r1c5==|(26)r1c35-|
|(3)-(3=6)r1c3-|r3c4=|
|(8)-(8=6)r4c4-|

=> -26 r1c2

(*b)
Code: Select all
r5c6:
|(7)-----------------------------------------------------------------------------|-(7)r5c8
|(5)-r8c6=(5-2)r8c4=r8c7-(2=7)r9c7-r3c7=(7)r3c8----------------------------------|
|(1)-r5c1=|(7)-------------------------------------------------------------------|
          |(6)-r3c1=r3c4-r1c5=(6-4)r4c5=r8c5-(4=92)r8c78-|(2=7)r9c7-r3c7=(7)r3c8-|
          |(9)-r5c3=r9c3-(9=2)r9c2-----------------------|

=> -7 r5c8

(*c)
Code: Select all
r4c2:
|(3)-r6c3==========================================|=(8)r6c3
|(4)-r4c5=(4-8)r8c5=r9c5-r9c3======================|
|(6)-r4c45=(6-5)r5c4=r8c4-(5=3)r8c6-(3=8)r9c5-r9c3=|
|(7)-r4c7=r9c7-(7=3)r9c9-(3=8)r9c5-r9c3============|

=> +8 r6c3

Looking back at my first two pathetic attempts (just found the notes and laughed)... yeah, I think I've learned something :) For that I can thank a lot of people here, mostly the same ones who kindly replied to this very first post of mine and gave tips on how to move forward. Still a lot to learn.

The one thing that hasn't changed, however, is the pencil&paper solving system I developed last year. It's been stable since October, and I can't think of any more improvements (to the core at least). I'm very happy with it, except for the slowness. That's why my next ambition would be to turn it into software, but we'll see if that ever happens. Until then I'm stuck with p&p. (I'm not principled about that at all -- I'd switch to computerized solving immediately if any program had the features I want, but none do.)

The puzzle (again):

000900030004700600081054002005000000000020308000090060000070800017000000400106050
Code: Select all
   *             |    |               |    |    *
        *        |=()=|    /  _  \    |=()=|               *
            *    |    |   |-=( )=-|   |    |      *
     *                     \  ¯  /                   *   
SpAce
 
Posts: 605
Joined: 22 May 2017

Re: Where to find extreme(+) puzzles?

Postby creint » Thu Mar 22, 2018 9:02 pm

With computerized solving do you mean: support for manual inputting logic?
What options should the program have and whats wrong with xsudo?
Maybe i can add some things to my solver.
creint
 
Posts: 41
Joined: 20 January 2018

Re: Where to find extreme(+) puzzles?

Postby SpAce » Fri Mar 23, 2018 1:10 am

creint wrote:With computerized solving do you mean: support for manual inputting logic?

I'm not quite sure what you mean by that. I haven't used Xsudo so I don't really know how it works in that.

What options should the program have?

What I really want is the same unique way of representing the candidate grid (+ some helper views) which I now draw by hand. Without it I wouldn't be able to solve harder puzzles, or at least it would be painful. In the playing mode I don't want any features that I wouldn't be able to do manually on paper, and I don't want it to make cheating too easy when stuck. In other words, I want it to provide tools for solving but not solve for me (unless I specifically ask for it, but then I'm no longer playing). For training, practicing, and post-game analysis the program should have other features as well -- but most what I want I already have in Hodoku, for example.

The main benefits of a software implementation of my system would be speed, better graphics, and automated syncing of multiple views. Reliability is not an issue, as I usually solve months without making a single mistake (and I do everything by hand, including basics).

and whats wrong with xsudo?

The first thing wrong with it is that it requires Windows, which is why I can't say much about else. I guess I could install it on a virtual box but I haven't been interested enough yet. It also seems to require a bit different solving philosophy, but that's not necessarily a bad thing. I think it might be especially good for solving or at least understanding some really difficult puzzles that aren't solvable with any "normal" methods. I don't think I'll be having such ambitions any time soon.

Maybe i can add some things to my solver.

Is your solver publicly available? I've understood from your other posts that it supports all kinds of sudoku variants, which is cool.
Code: Select all
   *             |    |               |    |    *
        *        |=()=|    /  _  \    |=()=|               *
            *    |    |   |-=( )=-|   |    |      *
     *                     \  ¯  /                   *   
SpAce
 
Posts: 605
Joined: 22 May 2017

Re: Where to find extreme(+) puzzles?

Postby champagne » Fri Mar 23, 2018 3:18 am

David P Bird wrote:GF the 'Senior Exocet' variation described in the compendium allows target cells to be outside the base cell band. It can just about be classed as a recognisable pattern as it consists of a defninite number of elements that can be checked without needing to track chains. But Champagne's base cells and targets are all in the same band so it does not apply.
David
.


Hi David,

I did not work on that topic for long, but the definition of an exoccet accepts the 2 cells in any place. At the very beginning, I explored all cells pairs. Later, when the JE appeared and lacking of interesting examples with cells outside the band, I concentrated on a band.

Later this year, I could restart some exploration on potential hardest with no known exotic pattern.
champagne
2017 Supporter
 
Posts: 6614
Joined: 02 August 2007
Location: France Brittany

Re: Where to find extreme(+) puzzles?

Postby David P Bird » Fri Mar 23, 2018 8:02 am

Champagne,

You wrote:Later this year, I could restart some exploration on potential hardest with no known exotic pattern.

I look forward to seeing what you can find!

One area that might be worth exploring is Almost Multifish (or Almost MSLS), where the list of pattern elimination cells includes one false one. Sometimes, but not often, it is possible to adjust the cover sets to correct this. It would be interesting to see if you can identify which of the eliminations must be right. PJP is also interested in this and his solver uses some brute force checking to find them I believe.

David
.
David P Bird
2010 Supporter
 
Posts: 1040
Joined: 16 September 2008
Location: Middle England

Re: Where to find extreme(+) puzzles?

Postby champagne » Fri Mar 23, 2018 10:40 am

Hi David,

I remember to have tried to combine several "rank 1" logic systems to produce a new exotic pattern, without succes at that time. Using a "rank 1" logic in a chain as some do with ALS is not a big problem, but following eleven's remarks, this is usually not a process that a manual player could apply.

We'll reopen the discussion in due time.
champagne
2017 Supporter
 
Posts: 6614
Joined: 02 August 2007
Location: France Brittany

Previous

Return to General