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Clement
Joined: 24 Apr 2006
Posts: 1110
Location: Dar es Salaam Tanzania
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 Posted: Sun Jan 03, 2010 10:29 pm Post subject: Jan 4 VH |
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XY-Wing - <34>-<46>-<36> eliminating 3 in r6c3 solves the puzzle.
There is also a UR-Type 1 <28> in r23c27 which solves it. |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Mon Jan 04, 2010 12:38 am Post subject: |
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A BUG+2 condition or a xy-wing13-4 with both pincer being transported are also one steppers.
Ted |
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storm_norm
Joined: 18 Oct 2007
Posts: 1741
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| Posted: Wed Jan 06, 2010 1:52 am Post subject: |
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trying something different...
sudocue offers a optimizing function and a canonacalizing functiong...
when I use those features on this puzzle the result looks like the puzzle below.
I guess i would have ask the moderators if its against the site's policy to rearrange the puzzle and make it a tad more difficult???
Marty?
Keith?
if not then an optimized version of the VH might be worth exploring in these threads, especially if they require just a tad more than the normal x,xy,xyz-wings to solve.
A.K.A. VH+ type puzzle, but nothing extreme.
just an idea... here is an example from the VH in this thread.
000000001000002030412050600000000007005006040023070800000003000106020300907600000
| Code: |
+-------+-------+-------+
| . . . | . . . | . . 1 |
| . . . | . . 2 | . 3 . |
| 4 1 2 | . 5 . | 6 . . |
+-------+-------+-------+
| . . . | . . . | . . 7 |
| . . 5 | . . 6 | . 4 . |
| . 2 3 | . 7 . | 8 . . |
+-------+-------+-------+
| . . . | . . 3 | . . . |
| 1 . 6 | . 2 . | 3 . . |
| 9 . 7 | 6 . . | . . . |
+-------+-------+-------+
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Play online
this puzzle does not solve with the normal xy-wing even tho its based entirely on its VH cousin.
comments?
opinions?
rants?
raves? |
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arkietech
Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA
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| Posted: Wed Jan 06, 2010 2:42 am Post subject: |
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| I just needed a turbot 1. Did I miss something? |
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storm_norm
Joined: 18 Oct 2007
Posts: 1741
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| Posted: Wed Jan 06, 2010 2:53 am Post subject: |
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| no |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Wed Jan 06, 2010 4:53 am Post subject: |
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| Quote: | I guess i would have ask the moderators if its against the site's policy to rearrange the puzzle and make it a tad more difficult???
Marty?
Keith? |
Can't speak for Keith, but I was made a moderator without guidelines or policies. But go ahead, that seems a legitimate topic. |
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Wendy W
Joined: 04 Feb 2008
Posts: 144
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| Posted: Sun Jan 10, 2010 12:29 am Post subject: |
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Norm, I got this far but I'm not seeing the turbot...can you help? Thanks.
+---------+-----------------+---------------+
| 3 67 89 | 4789 4689 4789 | 5 2 1 |
| 5 67 89 | 1789 1689 2 | 479 3 489 |
| 4 1 2 | 3 5 789 | 6 789 89 |
+---------+-----------------+---------------+
| 8 4 1 | 259 3 59 | 29 6 7 |
| 7 9 5 | 128 18 6 | 12 4 3 |
| 6 2 3 | 149 7 149 | 8 159 59 |
+---------+-----------------+---------------+
| 2 58 4 | 15789 189 3 | 179 1789 6 |
| 1 58 6 | 45789 2 4789 | 3 789 4589 |
| 9 3 7 | 6 148 1458 | 14 158 2 |
+---------+-----------------+---------------+ |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Sun Jan 10, 2010 12:35 am Post subject: |
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Here's the grid from the above post:
| Code: | +---------+-----------------+----------------+
| 3 67 89 | 4789 4689 4789 | 5 2 1 |
| 5 67 89 | 1789 1689 2 | 479 3 489 |
| 4 1 2 | 3 5 789 | 6 789 89 |
+---------+-----------------+----------------+
| 8 4 1 | 259 3 59 | 29 6 7 |
| 7 9 5 | 128 18 6 | 12 4 3 |
| 6 2 3 | 149 7 149 | 8 159 59 |
+---------+-----------------+----------------+
| 2 58 4 | 15789 189 3 | 179 1789 6 |
| 1 58 6 | 45789 2 4789 | 3 789 4589 |
| 9 3 7 | 6 148 1458 | 14 158 2 |
+---------+-----------------+----------------+ |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Sun Jan 10, 2010 1:20 am Post subject: |
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| Marty R. wrote: | Here's the grid from the above post:
| Code: | +---------+-----------------+----------------+
| 3 67 89 | 4789 4689 4789 | 5 2 1 |
| 5 67 89 | 1789 1689 2 | 479 3 489 |
| 4 1 2 | 3 5 789 | 6 789 89 |
+---------+-----------------+----------------+
| 8 4 1 | 259 3 59 | 29 6 7 |
| 7 9 5 | 128 18 6 | 12# 4 3 |
| 6 2 3 | 149 7 149@ | 8 159@ 59 |
+---------+-----------------+----------------+
| 2 58 4 | 15789 189 3 | 179 1789 6 |
| 1 58 6 | 45789 2 4789 | 3 789 4589 |
| 9 3 7 | 6 148 1458# |-14 158 2 |
+---------+-----------------+----------------+ |
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One of @ in R6 is not true: On of # in C6, B6 is true: R9C7 is not 1.
Keith |
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Wendy W
Joined: 04 Feb 2008
Posts: 144
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| Posted: Sun Jan 10, 2010 2:04 am Post subject: |
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| Thanks, guys! I'm still having trouble grasping the whole turbot concept. Can you talk me through how you would go about spotting this? |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Sun Jan 10, 2010 3:46 am Post subject: |
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| Wendy W wrote: | | Thanks, guys! I'm still having trouble grasping the whole turbot concept. Can you talk me through how you would go about spotting this? |
Some may not agree, but:
Turbot fish is a generic name that includes skyscrapers, kites, and most empty rectangles (hinges). These are all based on the simplest form of multi-coloring, two strong links.
A great introduction is Havard's paper on strong links:
http://www.sudoku.com/boards/viewtopic.php?t=3326
Then, you could look up Turbot Fish at Sudopedia and other sites.
How do you spot them? It's in the eye of the beholder.
As a start, how do you spot an X-wing? I look for a strong link, then I look for another strong link that lines up on both ends.
How do you find a Turbot? Look for a strong link, then look for another strong link that lines up on one end. Where they line up, one must be false; at the other ends (pincers), one must be true.
The current puzzle is a great example, and probably is the hardest variant to spot.
I wrote this a couple of weeks ago:
http://www.dailysudoku.com/sudoku/forums/viewtopic.php?t=4120
It did not get much reaction, but I have found it to be a great help when solving with pencil & paper.
Look at the nine boxes in a Sudoku grid. Eliminate all boxes where the candidate is solved. Eliminate all boxes where the candidate exists only in one row or one column. A Turbot elimination is only possible if the remaining boxes are on a rectangle. If an elimination exists, the links, and the elimination, are in that rectangle.
| Code: | +---------+-----------------+----------------+
| 3 67 89 | 4789 4689 4789 | 5 2 1 |
| 5 67 89 | 1789 1689 2 | 479 3 489 |
| 4 1 2 | 3 5 789 | 6 789 89 |
+---------+-----------------+----------------+
| 8 4 1 | 259 3 59 | 29 6 7 |
| 7 9 5 | 128 18 6 | 12 4 3 |
| 6 2 3 | 149 7 149 | 8 159 59 |
+---------+-----------------+----------------+
| 2 58 4 | 15789 189 3 | 179 1789 6 |
| 1 58 6 | 45789 2 4789 | 3 789 4589 |
| 9 3 7 | 6 148 1458 | 14 158 2 |
+---------+-----------------+----------------+ |
Let's look at where 1 is solved (/)
| Code: | +-+-+-+
|/|.|/|
+-+-+-+
|/|.|.|
+-+-+-+
|/|.|.|
+-+-+-+ |
Furthermore in B2 the candidates for 1 are only in R2. So, we have:
| Code: | +-+-+-+
|/|/|/|
+-+-+-+
|/|.|.|
+-+-+-+
|/|.|.|
+-+-+-+ |
If there is a Turbot elimination on 1, the start and end points of the strong links, and the elimination, must lie in B5689.
Using this logic, you can quickly see that Turbot eliminations in this puzzle are not possible for 3 (solved), or for 2,4,5,6. You only need to look at 1, 7, 8, 9.
Keith |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Sun Jan 10, 2010 4:58 am Post subject: |
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| Wendy W wrote: | | Thanks, guys! I'm still having trouble grasping the whole turbot concept. Can you talk me through how you would go about spotting this? |
Turbot fish are really fun once you understand them. I think multiple colors provides a nice (visual) understanding. Here's the candidate grid for <1>.
| Code: | Classic Turbot Fish
----------------------------------------------
[c6] colored Blue/Green
[b6] colored Pink/Amber
Since Blue sees Amber in [r6]
r9c7<>1 follows because it sees Green and Pink
+-----------------------------------+
| . . . | . . . | . . 1 |
| . . . | 1 1 . | . . . |
| . 1 . | . . . | . . . |
|-----------+-----------+-----------|
| . . 1 | . . . | . . . |
| . . . | 1 1 . | 1P . . |
| . . . | 1 . 1B | . 1A . |
|-----------+-----------+-----------|
| . . . | 1 1 . | 1 1 . |
| 1 . . | . . . | . . . |
| . . . | . 1 1G | -1 1 . |
+-----------------------------------+
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| Code: | Grouped 2-String Kite
----------------------------------------------
[c6] colored Blue/Green
[r5] colored Pink/Amber
Since Blue sees (both) Amber in [b5]
r9c7<>1 follows because it sees Green and Pink
+-----------------------------------+
| . . . | . . . | . . 1 |
| . . . | 1 1 . | . . . |
| . 1 . | . . . | . . . |
|-----------+-----------+-----------|
| . . 1 | . . . | . . . |
| . . . | 1A 1A . | 1P . . |
| . . . | 1 . 1B | . 1 . |
|-----------+-----------+-----------|
| . . . | 1 1 . | 1 1 . |
| 1 . . | . . . | . . . |
| . . . | . 1 1G | -1 1 . |
+-----------------------------------+
|
This is a bit off the beaten path for turbot fish, but it works.
| Code: | finned X-Wing
-----------------------------------------------------
[c6] colored Blue/Green
[c8] colored Pink/Amber
Since Blue sees Amber in [r6]
r9c7<>1 follows because it sees Green and (both) Pink
+-----------------------------------+
| . . . | . . . | . . 1 |
| . . . | 1 1 . | . . . |
| . 1 . | . . . | . . . |
|-----------+-----------+-----------|
| . . 1 | . . . | . . . |
| . . . | 1 1 . | 1 . . |
| . . . | 1 . 1B | . 1A . |
|-----------+-----------+-----------|
| . . . | 1 1 . | 1 1P . |
| 1 . . | . . . | . . . |
| . . . | . 1 1G | -1 1P . |
+-----------------------------------+
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Unfortunately, this grid doesn't contain an example for Skyscraper or Empty Rectangle. However, it can easily be altered to demonstrate a Skyscraper ... by removing <1> in r9c8.
| Code: | Skyscraper -or- (2x) Sashimi X-Wing
----------------------------------------------------
[c6] colored Blue/Green
[c8] colored Pink/Amber
Since Blue sees Amber in [r6]
r7c45,r9c7<>1 follow because they see Green and Pink
+-----------------------------------+
| . . . | . . . | . . 1 |
| . . . | 1 1 . | . . . |
| . 1 . | . . . | . . . |
|-----------+-----------+-----------|
| . . 1 | . . . | . . . |
| . . . | 1 1 . | 1 . . |
| . . . | 1 . 1B | . 1A . |
|-----------+-----------+-----------|
| . . . | -1 -1 . | 1 1P . |
| 1 . . | . . . | . . . |
| . . . | . 1 1G | -1 . . |
+-----------------------------------+
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Wendy W
Joined: 04 Feb 2008
Posts: 144
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| Posted: Sun Jan 10, 2010 4:35 pm Post subject: |
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| Thanks so much for your explanations. With the Eagles' season finished (American football), I will have time this afternoon to sit down and try to digest all this fishiness. Somehow I don't remember having this much trouble when I made the jump to VH puzzles! |
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