need help with this puzzle, and technique in general

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Re: need help with this puzzle, and technique in general

Postby 200e200w » Sat Feb 03, 2018 10:10 am

Hi, SpAce!
Is there good (or any) documentation available for the techniques SE uses? Some of the names it uses aren't quite standard, so it would be helpful to know their correspondence with more familiar names.

I wrote a compendium of some solving techniques used by SE. They are Unique Loops, BUG type 2, 3 and 4, and all techniques from Bidirectional X-Cycle and up to the highest currently known level of Nested Forcing Chains, with their usual ratings. It is posted here as an attachment. You should be able to open it with any textual editor.

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SE Techniques.txt
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Re: need help with this puzzle, and technique in general

Postby SpAce » Sat Feb 03, 2018 10:04 pm

Thanks a lot, 200e200w! I appreciate it. That provides a much better picture of what's going on.
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Re: need help with this puzzle, and technique in general

Postby 200e200w » Sat Feb 03, 2018 10:11 pm

Note that there is a small typo in Aligned Triplet Exclusion description, should be:
Hidden Text: Show
Aligned Triplet Exclusion - like Aligned Pair Exclusion (which is not listed there because it is used in Andrew's solver), but eliminates candidates from three cells, instead of two. Rated 7.5.


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Re: need help with this puzzle, and technique in general

Postby SpAce » Sat Feb 03, 2018 11:04 pm

200e200w wrote:Note that there is a small typo in Aligned Triplet Exclusion description, should be:
Hidden Text: Show
Aligned Triplet Exclusion - like Aligned Pair Exclusion (which is not listed there because it is used in Andrew's solver), but eliminates candidates from three cells, instead of two. Rated 7.5.

About that... I've been wondering if any human players actually use either? APE is one of the techniques I always switch off if I run the SudokuWiki solver, because I'd never look for (nor probably spot) those things myself. It seems pretty T&E and quite tedious at that to me, except maybe in some very obvious situations. Perhaps there are some heuristics that help to spot them easily as patterns but I haven't noticed (nor really tried either).
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Re: need help with this puzzle, and technique in general

Postby StrmCkr » Sun Feb 04, 2018 1:58 am

most of the ape,apt, death blossom, and sue de coq types are easier to spot and use when they are considered as subset exclusion rules
doubly linked als-xz rules, als-xy rules, als-chain rules

for the most part ape, apt, are used on that website and not much on the forums and are basically obsolete as a more powerful technique was developed off them with less 'counting" so to speak {almost locked set types}

for a point of interest these also all fall under disjointed Distributed subset technique which also covers all the above stuff as well, but harder to use.
Some do, some teach, the rest look it up.
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Re: need help with this puzzle, and technique in general

Postby SpAce » Sun Feb 04, 2018 3:14 am

StrmCkr, thanks for confirming my suspicions!
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Re: need help with this puzzle, and technique in general

Postby SpAce » Sun Feb 04, 2018 7:18 am

As an exercise relating to recent discussions in another thread, I tried to turn 200e200w's krakens into AIC-like nets. No, I'm not suggesting they're an improvement in any way :) Let's see...

200e200w wrote:Kraken Finned X-Wing.
Finned X-Wing: 8 r78/c18 fr7c5,r8c2
(8)r7c1 - (8=56)r34c1 - (5=136)r124c5 - 3r2c4
(8-3)r7c5 = r7c4 - r2c4
(8)r8c1 - (8=56)r34c1 - (5=136)r124c5 - 3r2c4
(8)r8c2 - (8=56)r58c8 - 5r5c2 = r4c12 - (5=136)r124c5 - 3r2c4
=> -3 r2c4[/code]

My version:

Code: Select all
.------------------------.----------------------.---------------------.
|   3       5689   1689  |  2     g16     4     | 15689  7      5689  |
|   4569    7      1469  | x6-3   g1(3)6  8     | 1569   2      569   |
|  D68      2      168   |  7      9      5     | 168    4      3     |
:------------------------+----------------------+---------------------:
|F'D568   F'3568   368   |  4     g56     1     | 2      9      7     |
|   2     E'569    69    |  8      7      3     | 4    D'56     1     |
|   1       4      7     |  569    2      69    | 568    3      568   |
:------------------------+----------------------+---------------------:
|  C679*8   1      2     |a(3)569 b356#8  679   | 569    56*8   4     |
|  C679*8 C'69#8   5     |  1      4      679   | 3    D'6*8    2     |
|   4689    3689   34689 |  569    568    2     | 7      1      569   |
'------------------------'----------------------'---------------------'

(3)r7c4 = (3-8)r7c5 = [Finned X-Wing 8 r78/c18 fr8c2]: [(8) r78c1|r8c2] - [r34c1,r58c8] = [(6,5)r34c1 | [(5,6)r58c8-(5)r5c2=r4c12]] - (5=6,1,3)r412c5

=> (3r7c4 | 3r2c5) => -3 r2c4

Yes, I also think it's ugly as hell :D The other one:

Code: Select all
Kraken Finned Franken X-Wing.
Finned Franken X-Wing: 9 r69/c4b7 fr6c6,r9c9
(9-6)r6c6 = r6c79 - (6=5)r5c8 - r5c2
(9-4)r9c1 = (4-5)r2c1 = r4c1 - r5c2
(9)r9c2 - r789c1 = (9-5)r2c1 = r4c1 - r5c2
(9)r9c3 - r5c3 = (9-5)r5c2
(9)r9c9 - (9=5)r2c9 - r2c1 = r4c1 - r5c2
=> -5 r5c2

My version (I used the same chain for the c2 and c3 branches to keep things a bit simpler):

Code: Select all
.---------------------------.---------------------.---------------------.
|    3       5689    689    | 2      1      4     | 5689   7      5689  |
|   f459     7       149    | 6      3      8     | 159    2   E''59    |
|    68      2       168    | 7      9      5     | 168    4      3     |
:---------------------------+---------------------+---------------------:
|  g(5)68    3568    368    | 4      56     1     | 2      9      7     |
|    2      x6-5     69     | 8      7      3     | 4    a(5)6    1     |
|    1       4       7      | 5*9    2     c6#9   |b568    3     b568   |
:---------------------------+---------------------+---------------------:
|  E'6789    1       2      | 3      568    679   | 569    568    4     |
|  E'6789    689     5      | 1      4      679   | 3      68     2     |
|E'ED468*9 D'368*9 D'3468*9 | 5*9    568    2     | 7      1   D''56#9  |
'---------------------------'---------------------'---------------------'

(5=6)r5c8 - r6c79 = (6-9)r6c6 = [Finned Franken X-Wing 9 r69/c4b7 fr9c9]: [(9) r9c1|r9c23|r9c9] - [(4)r9c1,(9)r789c1,r2c9] = [(4|9)r2c1 | (5)r2c9] - (5)r2c1 = (5) r4c1

=> -5 r5c2

Yes, it's ugly too, but is that actually a valid AIC (split-nodes only)? Then again, I think it's much simpler if we forget the fishy stuff and just use the row:

(5=6)r5c8 - r6c79 = (6-9)r6c6 = r6c4 - r9c4 = [r9c1|r9c23|r9c9] - [(4)r9c1,(9)r789c1,r2c9] = [(4|9)r2c1 | (5)r2c9] - (5)r2c1 = (5)r4c1

That's not so bad, is it?
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