The New Sudoku Players' Forum

[ravel]

Three more of them:

Code: Select all

 +-------+-------+-------+
 | . . 1 | 5 . 2 | . 3 . |
 | . . . | . . 1 | . . 9 |
 | 4 . . | 7 . . | . 2 . |
 +-------+-------+-------+
 | . . 2 | . 6 . | . . 8 |
 | 6 . . | . . . | . . 1 |
 | 8 . . | . 1 . | 4 . . |
 +-------+-------+-------+
 | . 4 . | . . 9 | . . 2 |
 | 7 . . | 6 . . | . . . |
 | . 5 . | 4 . 3 | 6 . . |
 +-------+-------+-------+

 +-------+-------+-------+
 | 5 . . | 2 . 1 | . . 3 |
 | 9 . . | 3 . . | . 8 1 |
 | . . 4 | . . . | . . . |
 +-------+-------+-------+
 | . . . | 9 . . | 5 2 8 |
 | . . . | . . . | . . . |
 | 6 3 9 | . . 5 | . . . |
 +-------+-------+-------+
 | . . . | . . . | 1 . . |
 | 4 6 . | . . 2 | . . 5 |
 | 2 . . | 4 . 3 | . . 9 |
 +-------+-------+-------+

 +-------+-------+-------+
 | . . 3 | . . 6 | 8 . . |
 | . 1 . | 3 . . | . . . |
 | . . 5 | . 1 . | 3 . 4 |
 +-------+-------+-------+
 | 8 7 . | . . 2 | . . . |
 | . . . | . . . | . . . |
 | . . . | 1 . . | . 3 9 |
 +-------+-------+-------+
 | 6 . 7 | . 2 . | 5 . . |
 | . . . | . . 7 | . 2 . |
 | . . 9 | 4 . . | 7 . . |
 +-------+-------+-------+


[RW]

Thanks ravel, I've added your puzzles to the list. The good thing with your technique is that the puzzles automaticly have at least rotational symmetry and the puzzles are easy to check (I only need to check half of the puzzle for URs etc, if nothing solves the puzzle I know that there cannot be anything that solves it in the other half either ).

I added links to all the different techniques in the list. Most links I took directly from Mike Barkers list. If anybody has suggestions for better links to some particular technique, please say so. I couldn't really decide which Nice Loop thread to link, so that's the only one missing, suggestions are welcome. I also couldn't find a good thread that explains finned fish in a simple "for dummies" way, is there any such thread?

RW

[Mike Barker]

For finned fish try: http://forum.enjoysudoku.com/viewtopic.php?t=2793

The "everything you always wanted to know about nice loops" site is: http://forum.enjoysudoku.com/viewtopic.php?t=2143 , but Jeff's application threads may make better initial reading. The links to these and other techniques are summarized here

[udosuk]

For finned x-wings and more there is also this source where people have discussed using some colourful pics... The main focus there was for diagonal puzzles but I guess the basic principle works the same...

[fermat]

Is this xyz-wing suitable? It is easy, except for that step.

Code: Select all

5 4 . | . . . | . . .
2 . 8 | . . . | 5 1 .
. 7 1 | 5 . 3 | . 2 .
---------------------
. . 5 | 9 . . | 3 . .
. . . | . 1 . | . . .
. . 7 | . . 4 | 9 . .
---------------------
. 2 . | 7 . 9 | 1 3 .
. 6 3 | . . . | 2 . 4
. . . | . . . | . 6 8


[tarek]

Is this xyz-wing suitable? It is easy, except for that step.

This is not just an effortless extreme, It should also be in the benchmark Sudoku list.......

It needs only an XYZ wing following singles to crack, good one fermat ......

tarek

[fermat]

Is this xyz-wing suitable? It is easy, except for that step.

This is not just an effortless extreme, It should also be in the benchmark Sudoku list.......

It needs only an XYZ wing following singles to crack, good one fermat ......

tarek

Whew!! Thanks, I have tried several times to get a puzzle posted, I never seem to understand the rules.

[ronk]

This is not just an effortless extreme, It should also be in the benchmark Sudoku list.......

It needs only an XYZ wing following singles to crack, good one fermat

Depending upon technique ordering, it could also serve as a benchmark test for BUG+1 and supercoloring.

Code: Select all


 5   4   6   | 2   9   1   | 8   7   3
 2   3   8   | 46  47  67  | 5   1   9
 9   7   1   | 5   8   3   | 4   2   6
-------------+-------------+------------
 46  18  5   | 9   27  67  | 3   48  12
 34  9   2   | 38  1   5   | 6   48  7
 36  18  7   | 368 23  4   | 9   5   12
-------------+-------------+------------
 8   2   4   | 7   6   9   | 1   3   5
 7   6   3   | 1   5   8   | 2   9   4
 1   5   9   | 34  34  2   | 7   6   8

xyz-wing: r6c5<>3
BUG+1: r6c4=3
supercoloring: r2c6<>6, r4c1<>6, r6c4<>6

[RW]

Depending upon technique ordering, it could also serve as a benchmark test for BUG+1

ronk is right. I'm afraid I can't put it on the list as XYZ-wing, no other BUG+1s have made it under another technique either. The BUG+1 is always easier to spot than any other 'extreme' technique in a pm-grid, and I doubt many people are solving the puzzles in this list without pms...

RW

[Ruud]

Here is a puzzle that I planned to add to the Benchmark list, but I'll post it here first to see if anyone can prove me wrong.

Looking at Mike's list, both ALS samples also need other stuff. Not much, but enough to require some effort.

Since it's ALS-week at my place, I decided to look for a better sample.

It starts with 12 initial singles, 1 ALS-XZ and then completes with singles all the way.

Code: Select all

000970003000001800970804010009702060130000009280010070000608000061000000400000030

ALS-XZ: A=(r78c89:v12458), B=(r4c9:v18), X=1, Z=8
.---------------------.---------------------.---------------------.
| 68     1      258   | 9      7      56    | 2456   245    3     |
| 36     25     4     | 235    2356   1     | 8      9      7     |
| 9      7      235   | 8      2356   4     | 256    1      256   |
:---------------------+---------------------+---------------------:
| 5      4      9     | 7      38     2     | 13     6     B18    |
| 1      3      7     | 45     4568   56    | 245    2458   9     |
| 2      8      6     | 345    1      9     | 345    7      45    |
:---------------------+---------------------+---------------------:
| 37     259    235   | 6      2459   8     | 124579A245   A1245  |
| 78     6      1     | 245    2459   3     | 24579 A2458  A2458  |
| 4      259    258   | 1      259    7     | 2569   3      256-8 |
'---------------------'---------------------'---------------------'

Ruud

[tarek]

I posted a puzzle in the 1st page of this thread that has only 1 ALS-xy rule before that are single & after it only singles, so it is a benchmark ALS xy rule (not that many solvers use it though) ........The puzzle unfortunately is in my database & I can't confirm if it is mine or not

tarek

[Mike Barker]

The puzzle is great - exactly the kind of thing I look for. I would classify it under "generalized" VWXYZ-wing for which there are several other examples in the "zoo" as well as other ALS's. If its okay I'd like to add it to the zoo collection.

[daj95376]

For others like myself who don't understand ALS and its variants.

Code: Select all

[r8c1]=8 => [r9c9]=8 => [r4c9]=1 => [r78c89]=245 contradiction! => [r8c1]=7

[Ruud]

Bring it to the zoo, Mike.

I also have a mate for it:

Code: Select all

034000010100700500000600000000000000070002300620030059007059002390000085080001070

ALS: A=(r5c13459:v145689), B=(r8c4+r9c5:v246), X=6, Z=4

.---------------.---------------.---------------.
| 2789 3    4   | 259  289  58  | 278  1    6   |
| 1    6    289 | 7    2489 348 | 5    249  38  |
| 2789 5    289 | 6    1    348 | 2478 249  378 |
:---------------+---------------+---------------:
| 589  4    3   | 159  6789 5678| 278  26   178 |
|A589  7   A1589|A1459A4689 2   | 3    46  A18  |
| 6    2    18  | 1-4  3    478 | 478  5    9   |
:---------------+---------------+---------------:
| 4    1    7   | 8    5    9   | 6    3    2   |
| 3    9    26  |B24   2467 467 | 1    8    5   |
| 25   8    256 | 3   B26   1   | 9    7    4   |
'---------------'---------------'---------------'

Can you turn this into any other technique?

Ruud

[Mike Barker]

This one is a question of hierarchy. First it contains a couple of unnecessary UR's. I put advanced coloring before ALS's and the puzzle can be solved with 3 advanced coloring nice loops (not a very appealing solution, but its there). If I disable UR's and nice loops, then the next technique my solver picks up is an Almost Fish which I thought was pretty cool where r8c3<>2 and which leaves just singles:

Code: Select all

+----------------+-------------------+-----------------+
|  2789  3     4 |   259   289    58 |   278    1    6 |
|     1  6  @289 |     7  2489   348 |     5  249   38 |
|  2789  5  @289 |     6     1   348 |  2478  249  378 |
+----------------+-------------------+-----------------+
|   589  4     3 |  *159  6789  5678 |   278   26 *178 |
|   589  7 *1589 | *1459  4689     2 |     3   46  *18 |
|     6  2   @18 |   #14     3   478 |   478    5    9 |
+----------------+-------------------+-----------------+
|     4  1     7 |     8     5     9 |     6    3    2 |
|     3  9   -26 |   #24  2467   467 |     1    8    5 |
|    25  8   256 |     3    26     1 |     9    7    4 |
+----------------+-------------------+-----------------+

I also get an ALS which leaves just singles, but is somewhat simpler than the one shown and much simpler than the Almost Fish:

Code: Select all

+----------------+-------------------+-----------------+
|  2789  3     4 |   259   289    58 |   278    1    6 |
|     1  6  #289 |     7  2489   348 |     5  249   38 |
|  2789  5  #289 |     6     1   348 |  2478  249  378 |
+----------------+-------------------+-----------------+
|   589  4     3 |   159  6789  5678 |   278   26  178 |
|   589  7  1589 |  1459  4689     2 |     3   46   18 |
|     6  2   #18 |   *14     3   478 |   478    5    9 |
+----------------+-------------------+-----------------+
|     4  1     7 |     8     5     9 |     6    3    2 |
|     3  9   -26 |   *24  2467   467 |     1    8    5 |
|    25  8   256 |     3    26     1 |     9    7    4 |
+----------------+-------------------+-----------------+

I think I need to move Almost Fish after ALS.