| View previous topic :: View next topic |
| Author |
Message |
keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
|
 Posted: Sat Feb 28, 2009 8:36 pm Post subject: The best Sudoku puzzle ever? |
 |
|
This puzzle was posted by Norm on Tuesday. I don't think it got enough attention. It is just about the nicest puzzle I have ever seen!
http://www.dailysudoku.com/sudoku/forums/viewtopic.php?t=3283
I don't think it got enough attention, and the original thread wandered into a discussion of terminology concerning a second puzzle that Norm posted in the same thread.
| Quote: | this puzzle by metcalf is rated 7.0 by SE
| Code: |
+-------+-------+-------+
| . . 1 | . 2 . | . 3 . |
| 4 5 . | . . 3 | . 6 . |
| . . 3 | . . . | 5 . 7 |
+-------+-------+-------+
| . 1 . | . 8 . | . . . |
| 5 . . | 2 . 6 | . . 8 |
| . . . | . 9 . | . 5 . |
+-------+-------+-------+
| 6 . 4 | . . . | 2 . . |
| . 9 . | 7 . . | . 8 6 |
| . 8 . | . 6 . | 3 . . |
+-------+-------+-------+
|
Play this puzzle online at the Daily Sudoku site |
When I first solved the puzzle, I had eight advanced steps. I am sure some of them are not necessary, like the ER in this next situation.
After basics, note that no cells have been solved! | Code: | +-------------------+-------------------+-------------------+
| 789 67 1 | 45689 2 45789 | 489 3 49 |
| 4 5 2789 | 189 17 3 | 189 6 129 |
| 289 26 3 | 14689 14 1489 | 5 1249 7 |
+-------------------+-------------------+-------------------+
| 2379 1 2679 | 345 8 457 | 4679 249 2349 |
| 5 347 79 | 2 1347 6 | 1479 149 8 |
| 2378 2347 2678 | 134 9 147 | 1467 5 1234 |
+-------------------+-------------------+-------------------+
| 6 37 4 | 1389 135 189 | 2 179 159 |
| 123 9 25 | 7 1345 124 | 14 8 6 |
| 127 8 257 | 149 6 1249 | 3 1479 1459 |
+-------------------+-------------------+-------------------+ |
Enjoy!
Keith |
|
| Back to top |
|
 |
wapati
Joined: 10 Jun 2008
Posts: 472
Location: Brampton, Ontario, Canada.
|
| Posted: Sun Mar 01, 2009 3:37 am Post subject: |
|
|
| cross post |
|
| Back to top |
|
|
cgordon
Joined: 04 May 2007
Posts: 769
Location: ontario, canada
|
| Posted: Sun Mar 01, 2009 2:52 pm Post subject: |
|
|
It took me forever to get going - but once I found the ER on <3> the puxzzle opened up. After three more ERs on <1>, an x wing on <7> and an xy wing <149> - it seized up. This is as far as I can get (sorry for misaligned grid)
| Code: |
+---------+--------------+---------+
| 7 6 1 |4589 2 4589 |48 3 49|
| 4 5 9 |18 7 3 |18 6 2|
| 8 2 3 |6 14 149 |5 149 7|
+---------+-------------+---------+
| 9 1 6 |345 8 45 |7 2 34|
| 5 34 7 |2 134 6 |9 14 8|
| 2 34 8 |134 9 7 |6 5 134|
+---------+--------------+----------+
| 6 7 4 | 389 35 189 | 2 19 159|
| 3 9 25 | 7 145 124 | 14 8 6 |
| 1 8 25 | 49 6 249 | 3 7 459 |
+---------+--------------+-----------+
|
|
|
| Back to top |
|
|
Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
|
| Posted: Sun Mar 01, 2009 3:57 pm Post subject: |
|
|
Here is Craig's grid, aligned courtesy of Nataraj's format tool.
| Code: |
+---------+---------------+------------+
| 7 6 1 | 4589 2 4589 | 48 3 49 |
| 4 5 9 | 18 7 3 | 18 6 2 |
| 8 2 3 | 6 14 149 | 5 149 7 |
+---------+---------------+------------+
| 9 1 6 | 345 8 45 | 7 2 34 |
| 5 34 7 | 2 134 6 | 9 14 8 |
| 2 34 8 | 134 9 7 | 6 5 134 |
+---------+---------------+------------+
| 6 7 4 | 389 35 189 | 2 19 159 |
| 3 9 25 | 7 145 124 | 14 8 6 |
| 1 8 25 | 49 6 249 | 3 7 459 |
+---------+---------------+------------+
|
Play this puzzle online at the Daily Sudoku site |
|
| Back to top |
|
|
keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
|
| Posted: Sun Mar 01, 2009 5:43 pm Post subject: |
|
|
| Code: | +---------+---------------+------------+
| 7 6 1 | 4589 2 4589 | 48 3 49 |
| 4 5 9 |18# 7 3 |18# 6 2 |
| 8 2 3 | 6 14@ 149 | 5 149 7 |
+---------+---------------+------------+
| 9 1 6 | 345 8 45 | 7 2 34 |
| 5 34 7 | 2 134 6 | 9 14 8 |
| 2 34 8 | 134 9 7 | 6 5 134 |
+---------+---------------+------------+
| 6 7 4 | 389 35 189 | 2 19 159 |
| 3 9 25 | 7 1-45 124 |14@ 8 6 |
| 1 8 25 | 49 6 249 | 3 7 459 |
+---------+---------------+------------+ |
There is a W-wing that takes out <4> in R8C5.
Next hint: | Quote: | | Revealing an X-wing on <4> |
Keith |
|
| Back to top |
|
|
cgordon
Joined: 04 May 2007
Posts: 769
Location: ontario, canada
|
| Posted: Mon Mar 02, 2009 7:10 pm Post subject: |
|
|
Keith: I don't get your W-wing. My W-wing file says the two pairs have to be in the same chute - lined up with a strong link in the 3rd box
EG: (we can whack any <1> that sees both pairs)
| Code: |
+--------+--------+-------+
| 14 . . | . . . | . . 4 |
| . . . | . . . | . . . |
| . . . | 14 . . | . . 4 |
+--------+--------+-------+
| . . . | . . . | . . . |
| . . . | . . . | . . . |
| . . . | . . . | . . . |
+--------+--------+-------+
| . . . | . . . | . . . |
| . . . | . . . | . . . |
| . . . | . . . | . . . |
+--------+--------+-------+
|
|
|
| Back to top |
|
|
storm_norm
Joined: 18 Oct 2007
Posts: 1741
|
| Posted: Mon Mar 02, 2009 7:59 pm Post subject: |
|
|
| cgordon wrote: | Keith: I don't get your W-wing. My W-wing file says the two pairs have to be in the same chute - lined up with a strong link in the 3rd box
EG: (we can whack any <1> that sees both pairs)
| Code: |
+--------+--------+-------+
| 14 . . | . . . | . . 4 |
| . . . | . . . | . . . |
| . . . | 14 . . | . . 4 |
+--------+--------+-------+
| . . . | . . . | . . . |
| . . . | . . . | . . . |
| . . . | . . . | . . . |
+--------+--------+-------+
| . . . | . . . | . . . |
| . . . | . . . | . . . |
| . . . | . . . | . . . |
+--------+--------+-------+
|
|
Craig,
your notes should be revised to say that the strong link on 4's can be strong in either
box
row
column
its not exclusive to being strong in the same box.
and...
the pair you are connecting do not need to be in the same band either. |
|
| Back to top |
|
|
keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
|
| Posted: Mon Mar 02, 2009 8:03 pm Post subject: |
|
|
| cgordon wrote: | Keith: I don't get your W-wing. My W-wing file says the two pairs have to be in the same chute - lined up with a strong link in the 3rd box
EG: (we can whack any <1> that sees both pairs)
| Code: |
+--------+--------+-------+
| 14 . . | . . . | . . 4 |
| . . . | . . . | . . . |
| . . . | 14 . . | . . 4 |
+--------+--------+-------+
| . . . | . . . | . . . |
| . . . | . . . | . . . |
| . . . | . . . | . . . |
+--------+--------+-------+
| . . . | . . . | . . . |
| . . . | . . . | . . . |
| . . . | . . . | . . . |
+--------+--------+-------+
|
|
Your diagram is correct, but the pattern does not have to occur in one chute (floor, tower, ..). Here's my diagram: | Code: | +---------+---------------+------------+
| 7 6 1 | 4589 2 4589 | 48 3 49 |
| 4 5 9 |18B 7 3 |18C 6 2 |
| 8 2 3 | 6 14A 149 | 5 149 7 |
+---------+---------------+------------+
| 9 1 6 | 345 8 45 | 7 2 34 |
| 5 34 7 | 2 134 6 | 9 14 8 |
| 2 34 8 | 134 9 7 | 6 5 134 |
+---------+---------------+------------+
| 6 7 4 | 389 35 189 | 2 19 159 |
| 3 9 25 | 7 1-45 124 |14D 8 6 |
| 1 8 25 | 49 6 249 | 3 7 459 |
+---------+---------------+------------+ |
A and D have the same two candidates, <14>. BC is a strong link on <1>. (The fact that BC have the same two candidates is irrelevant here.) There are two possibilities:
A is <4>, or
A is <1>, B is not <1>, C is <1>, and D is <4>.
One or both of A and D are <4>, making the elimination shown.
By the way, when I did the puzzle, I did not see this as a W-wing. Rather I saw an extended XY-wing:
14 - 18 - 18 - 14, and you can make a pseudo cell <48> at either end. So, you have, for example 14 - 18 - 48 which acts like an XY-wing to eliminate <4>.
Best wishes,
Keith |
|
| Back to top |
|
|
cgordon
Joined: 04 May 2007
Posts: 769
Location: ontario, canada
|
| Posted: Mon Mar 02, 2009 9:57 pm Post subject: |
|
|
| Quote: | By the way, when I did the puzzle, I did not see this as a W-wing. Rather I saw an extended XY-wing:
14 - 18 - 18 - 14, and you can make a pseudo cell <48> at either end. So, you have, for example 14 - 18 - 48 which acts like an XY-wing to eliminate <4>.
|
OK. Thank you - I have updated my W wing file - but woah!! My files on Extended XY-Wings say the format is:
XZ-XY=XY=XY-YZ like 14-18-18-18-48
What you have appears to be nothing like that. |
|
| Back to top |
|
|
daj95376
Joined: 23 Aug 2008
Posts: 3854
|
| Posted: Mon Mar 02, 2009 10:32 pm Post subject: |
|
|
| cgordon wrote: | | Quote: | By the way, when I did the puzzle, I did not see this as a W-wing. Rather I saw an extended XY-wing:
14 - 18 - 18 - 14, and you can make a pseudo cell <48> at either end. So, you have, for example 14 - 18 - 48 which acts like an XY-wing to eliminate <4>.
|
OK. Thank you - I have updated my W wing file - but woah!! My files on Extended XY-Wings say the format is:
XZ-XY=XY=XY-YZ like 14-18-18-18-48
What you have appears to be nothing like that. |
I'm missing your example of an extended XY-Wing. However, here's my notes. Keith's example is listed as "Ext. #1".
| Code: | 3-cell XY-Chain; i.e., XY-Wing
** ** **
XY-Wing: ZX-XY-YZ => eliminations in Z
.. pivot
.. .. pincers
ZX = 12, XY = 23, YZ = 31
+-----------------------------------+
| . . . | . . . | . . . |
| . . . | . . . | . . . |
| . . . | . . . | . . . |
|-----------+-----------+-----------|
| . . . | 12 . . | . -1 . |
| . . . | . . . | . . . |
| . . . | . . . | . . . |
|-----------+-----------+-----------|
| . . . | . . . | . . . |
| . . . | 23 . . | . 31 . |
| . . . | . . . | . . . |
+-----------------------------------+
|
| Code: | 4-cell XY-Chain; i.e., XY-Wing with 2-cell pseudo-cell as center cell
** * * **
Ext. #1: ZX-XV-VY-YZ => eliminations in Z
ZX = 12, XV = 24, VY = 43, YZ = 31; XV-VY splits the 23 across two cells
+-----------------------------------+
| . . . | . . . | . . . |
| . . . | . . . | . . . |
| . . . | . . . | . . . |
|-----------+-----------+-----------|
| . . . | 12 . . | . -1 . |
| . . . | . . . | . . . |
| . . . | . . . | . . . |
|-----------+-----------+-----------|
| . . . | 24 . . | . . . |
| . . . | . . 43 | . 31 . |
| . . . | . . . | . . . |
+-----------------------------------+
|
| Code: | 5-cell XY-Chain; i.e., XY-Wing with two bivalue cells added
** ** **
Ext. #2: ZX-XY-YZ-ZW-WZ => eliminations in Z
Ext. #3: WZ-ZX-XY-YZ-ZW => eliminations in W
ZX = 12, XY = 23, YZ = 31, ZW = 16, WZ = 61
+-----------------------------------+
| . . . | . . . | . . . |
| . 61 . | . . . | . 16 . |
| . . . | . . . | . . . |
|-----------+-----------+-----------|
| . -1 . | 12 . . | . . . |
| . . . | . . . | . . . |
| . . . | . . . | . . . |
|-----------+-----------+-----------|
| . . . | . . . | . . . |
| . . . | 23 . . | . 31 . |
| . . . | . . . | . . . |
+-----------------------------------+
WZ = 61, ZX = 12, XY = 23, YZ = 31, ZW = 16
+-----------------------------------+
| . . . | . . . | . . . |
| . -6 . | . . . | . 16 . |
| . . . | . . . | . . . |
|-----------+-----------+-----------|
| . 61 . | 12 . . | . -6 . |
| . . . | . . . | . . . |
| . . . | . . . | . . . |
|-----------+-----------+-----------|
| . . . | . . . | . . . |
| . . . | 23 . . | . 31 . |
| . . . | . . . | . . . |
+-----------------------------------+
|
| Code: | 3-cell XY-Chain w/Strong Link (transport); i.e., XY-Wing w/transport
** ** ** @...@
Ext. #4: ZX-XY-YZ-Zw=vZ => eliminations in Z
ZX = 12, XY = 23, YZ = 31, Zw = 1w, vZ = v1
+-----------------------------------+
| . . . | . . . | . . . |
| / v1 / | / / / | / 1w / | strong link on <1> and other candidates ignored
| . . . | . . . | . . . |
|-----------+-----------+-----------|
| . -1 . | 12 . . | . . . |
| . . . | . . . | . . . |
| . . . | . . . | . . . |
|-----------+-----------+-----------|
| . . . | . . . | . . . |
| . . . | 23 . . | . 31 . |
| . . . | . . . | . . . |
+-----------------------------------+
|
With my notation, your chain would look like ...
| Code: | Craig Gordon; i.e., XY-Wing with 3-cell pseudo-cell as center cell
** * * **
Ext. #5: ZX-XY-YX-XY-YZ => eliminations in Z
ZX = 12, XY = 23, YX = 32, XY = 23, YZ = 31
+-----------------------------------+
| . . . | . . . | . . . |
| . 31 . | -1 . . | . 23 . |
| . . . | . . . | . . . |
|-----------+-----------+-----------|
| . -1 . | 12 . . | . . . |
| . . . | . . . | . . . |
| . . . | . . . | . . . |
|-----------+-----------+-----------|
| . . . | . . . | . . . |
| . . . | 23 . . | . 32 . |
| . . . | . . . | . . . |
+-----------------------------------+
|
Last edited by daj95376 on Tue Mar 10, 2009 3:29 pm; edited 4 times in total |
|
| Back to top |
|
|
cgordon
Joined: 04 May 2007
Posts: 769
Location: ontario, canada
|
| Posted: Mon Mar 02, 2009 10:51 pm Post subject: |
|
|
| Danny: You've gotta be kidding - right? I appreciate you trying to help - but that's way too abstruse. A picture is worth a thousand words. In its simplicity I am so proud of my little sketch above concerning W-wings. |
|
| Back to top |
|
|
keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
|
| Posted: Mon Mar 02, 2009 11:10 pm Post subject: |
|
|
Craig,
You are correct that people have used the term "extended XY-wing" to mean different short chains. I am guilty also.
Your example is correct, I think it is what you will find in my writeup on "Remote Pairs".
Then, we have "Pincer Coloring", which is another type of extension.
For the one I quoted above, I would prefer "4-cell XY chain".
Keith |
|
| Back to top |
|
|
daj95376
Joined: 23 Aug 2008
Posts: 3854
|
| Posted: Tue Mar 03, 2009 12:33 am Post subject: |
|
|
| cgordon wrote: | | Danny: You've gotta be kidding - right? I appreciate you trying to help - but that's way too abstruse. A picture is worth a thousand words. In its simplicity I am so proud of my little sketch above concerning W-wings. |
I updated my post to contain pictures! |
|
| Back to top |
|
|
nataraj
Joined: 03 Aug 2007
Posts: 1048
Location: near Vienna, Austria
|
| Posted: Tue Mar 03, 2009 7:03 am Post subject: Re: The best Sudoku puzzle ever? |
|
|
| keith wrote: | This puzzle was posted by Norm on Tuesday. I don't think it got enough attention. It is just about the nicest puzzle I have ever seen!
...
Enjoy!
Keith |
I finally got around to trying this one. Definitely a 3+ coffee puzzle.
Long, but perfectly doable by our usual tools and with p&p.
From my sketches, I had at least:
skyscraper (3) r58 (r7c2,r6c1 <> 3)
w-wing (4) r3c5=r8c7 (r8c5 <> 4)
x-wing (3) r46 (r7c4 <> 3)
xy-wing 19,14,49 pincers r3c6,r9c4 (r1c4,r7c6 <>> 9) and
skyscraper (1) r28 (r3c6 <> 1)
Funny I only used candidates 1 through 4, don't know which easy routes might exist in the upper ranks ... |
|
| Back to top |
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
