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arkietech
Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA
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 Posted: Tue May 04, 2010 2:40 am Post subject: A fun VH for the fourth of May |
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when you think you got it.. you don't | Code: | *-----------*
|9.8|..7|4..|
|4..|19.|...|
|.5.|..4|...|
|---+---+---|
|...|..6|.9.|
|3.7|.8.|5.6|
|.9.|5..|...|
|---+---+---|
|...|6..|.1.|
|...|.73|..2|
|..5|4..|3.9|
*-----------*
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Tue May 04, 2010 4:38 am Post subject: |
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| Quote: | XY-Wing (892)
W-Wing (67) |
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Mogulmeister
Joined: 03 May 2007
Posts: 1151
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| Posted: Tue May 04, 2010 1:16 pm Post subject: |
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Or a completely different 2 step:
1)AIC (23-8)r3c4=(8-5)r2c6=(5-9)r7c6=(9-8)=(8)r3c4 so r3c4 = 8
2)Colouring on 7s removes five 7s and puzzle is done. |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Tue May 04, 2010 1:51 pm Post subject: |
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I have added the "Naked Pair" technique to my VH/VH+ toolkit. I find that the pattern occurs frequently and that it easy to find. Here is an example.
| Code: | *--------------------------------------------------------------------*
| 9 1236 8 | 23 256 7 | 4 236 135 |
| 4 2367 236 | 1 9 #258 | 2678 23678 3578 |
| 1267 5 1236 | 238 26 4 | 9 23678 1378 |
|----------------------+----------------------+----------------------|
| 5 1248 124 | 7 34 6 | 128 9 38 |
| 3 124 7 | 29 8 129 | 5 24 6 |
| 1268 9 1246 | 5 34 12 | 1278 23478 378 |
|----------------------+----------------------+----------------------|
| 278 2378 239 | 6 25 2589 | 78 1 4 |
| 168 1468 1469 | 89 7 3 | 68 5 2 |
| 2678 2678 5 | 4 1 #28 | 3 678 9 |
*--------------------------------------------------------------------* |
The Naked Pair (NP) pattern is in r29c6, marked #. Either r2c6=28, which forms the naked pair with cell r9c6, or r2c6=5.
Thus: NP(28)r29c6 = (5)r2c6 - (5)r1c5 = (5-2)r7c5 = (2)r79c6; r6c6<>2
BUG+3 forces r7c1=8 to complete the puzzle.
Ted |
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Mogulmeister
Joined: 03 May 2007
Posts: 1151
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| Posted: Tue May 04, 2010 2:27 pm Post subject: |
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Very nice Ted - the almost naked pair makes the same eliminations as the <289> xy wing (it takes out the 2 in r5c6 as well doesn't it ?)
I like the BUG+3 at the end - not something I use a lot. |
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arkietech
Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA
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| Posted: Tue May 04, 2010 2:53 pm Post subject: |
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| tlanglet wrote: | | Code: | *--------------------------------------------------------------------*
| 9 1236 8 | 23 256 7 | 4 236 135 |
| 4 2367 236 | 1 9 #258 | 2678 23678 3578 |
| 1267 5 1236 | 238 26 4 | 9 23678 1378 |
|----------------------+----------------------+----------------------|
| 5 1248 124 | 7 34 6 | 128 9 38 |
| 3 124 7 | 29 8 129 | 5 24 6 |
| 1268 9 1246 | 5 34 12 | 1278 23478 378 |
|----------------------+----------------------+----------------------|
| 278 2378 239 | 6 25 2589 | 78 1 4 |
| 168 1468 1469 | 89 7 3 | 68 5 2 |
| 2678 2678 5 | 4 1 #28 | 3 678 9 |
*--------------------------------------------------------------------* |
NP(28)r29c6 = (5)r2c6 - (5)r1c5 = (5-2)r7c5 = (2)r79c6; r6c6<>2
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Would this be a "Finned Pair"? 
I like it! |
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Mogulmeister
Joined: 03 May 2007
Posts: 1151
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| Posted: Tue May 04, 2010 2:57 pm Post subject: |
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Good puzzle BTW Dan. |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Tue May 04, 2010 3:55 pm Post subject: |
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Formatted:
| Code: |
+-------+-------+-------+
| 9 . 8 | . . 7 | 4 . . |
| 4 . . | 1 9 . | . . . |
| . 5 . | . . 4 | . . . |
+-------+-------+-------+
| . . . | . . 6 | . 9 . |
| 3 . 7 | . 8 . | 5 . 6 |
| . 9 . | 5 . . | . . . |
+-------+-------+-------+
| . . . | 6 . . | . 1 . |
| . . . | . 7 3 | . . 2 |
| . . 5 | 4 . . | 3 . 9 |
+-------+-------+-------+
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Play this puzzle online at the Daily Sudoku site
Keith |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Tue May 04, 2010 4:31 pm Post subject: |
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| arkietech wrote: | | Would this be a "Finned Pair"? |
Dan,
I think I am going the route previously noted by Luke, and use the word "almost" for anything that is a standard pattern plus some additional stuff. So this pattern would be an almost naked pair (ANP). Other patterns would become "almost UR", "almost xy-wing", etc. This style of naming my not be considered the most accurate by some members of this forum, but it will at least be true and descrirtive.
Ted |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Tue May 04, 2010 8:32 pm Post subject: |
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This post was totally deleted. No sure why it was posted
Ted
Last edited by tlanglet on Wed May 05, 2010 1:07 pm; edited 1 time in total |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Wed May 05, 2010 1:43 am Post subject: |
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I too was drawn to the BUG+3 scenario. Here's a long-winded review.
| Code: | +-----------------------------------------------------------+
| 9 26 8 | 3 5 7 | 4 26 1 |
| 4 67 3 | 1 9 2 | 67 8 5 |
| 27 5 1 | 8 6 4 | 9 237 37 |
|-------------------+-------------------+-------------------|
| 5 48 2 | 7 34 6 | 1 9 38 |
| 3 1 7 | 2 8 9 | 5 4 6 |
| 68 9 46 | 5 34 1 | 2 37 378 |
|-------------------+-------------------+-------------------|
| 78 3 9 | 6 2 5 | 78 1 4 |
| 1 48 46 | 9 7 3 | 68 5 2 |
| 267 27 5 | 4 1 8 | 3 67 9 |
+-----------------------------------------------------------+
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<1>, <5>, and <9> are solved and can't contribute anything more to the solution.
| Code: | +-----------------------------------+
| . . . | . . . | . . 1 |
| . . . | 1 . . | . . . |
| . . 1 | . . . | . . . |
|-----------+-----------+-----------|
| . . . | . . . | 1 . . |
| . 1 . | . . . | . . . |
| . . . | . . 1 | . . . |
|-----------+-----------+-----------|
| . . . | . . . | . 1 . |
| 1 . . | . . . | . . . |
| . . . | . 1 . | . . . |
+-----------------------------------+
+-----------------------------------+
| . . . | . 5 . | . . . |
| . . . | . . . | . . 5 |
| . 5 . | . . . | . . . |
|-----------+-----------+-----------|
| 5 . . | . . . | . . . |
| . . . | . . . | 5 . . |
| . . . | 5 . . | . . . |
|-----------+-----------+-----------|
| . . . | . . 5 | . . . |
| . . . | . . . | . 5 . |
| . . 5 | . . . | . . . |
+-----------------------------------+
+-----------------------------------+
| 9 . . | . . . | . . . |
| . . . | . 9 . | . . . |
| . . . | . . . | 9 . . |
|-----------+-----------+-----------|
| . . . | . . . | . 9 . |
| . . . | . . 9 | . . . |
| . 9 . | . . . | . . . |
|-----------+-----------+-----------|
| . . 9 | . . . | . . . |
| . . . | 9 . . | . . . |
| . . . | . . . | . . 9 |
+-----------------------------------+
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<2>, <4>, <6>, and <8> form cycles that limit each to two solution possibilities.
A cycle by itself can't contribute anything more to the solution.
Overlaps in the cycles are useful but not convenient ... now.
| Code: | +-----------------------------------+
| . *2 . | . . . | . *2 . |
| . . . | . . 2 | . . . |
| *2 . . | . . . | . *2 . |
|-----------+-----------+-----------|
| . . 2 | . . . | . . . |
| . . . | 2 . . | . . . |
| . . . | . . . | 2 . . |
|-----------+-----------+-----------|
| . . . | . 2 . | . . . |
| . . . | . . . | . . 2 |
| *2 *2 . | . . . | . . . |
+-----------------------------------+
+-----------------------------------+
| . . . | . . . | 4 . . |
| 4 . . | . . . | . . . |
| . . . | . . 4 | . . . |
|-----------+-----------+-----------|
| . *4 . | . *4 . | . . . |
| . . . | . . . | . 4 . |
| . . *4 | . *4 . | . . . |
|-----------+-----------+-----------|
| . . . | . . . | . . 4 |
| . *4 *4 | . . . | . . . |
| . . . | 4 . . | . . . |
+-----------------------------------+
+-----------------------------------+
| . *6 . | . . . | . *6 . |
| . *6 . | . . . | *6 . . |
| . . . | . 6 . | . . . |
|-----------+-----------+-----------|
| . . . | . . 6 | . . . |
| . . . | . . . | . . 6 |
| *6 . *6 | . . . | . . . |
|-----------+-----------+-----------|
| . . . | 6 . . | . . . |
| . . *6 | . . . | *6 . . |
| *6 . . | . . . | . *6 . |
+-----------------------------------+
+-----------------------------------+
| . . 8 | . . . | . . . |
| . . . | . . . | . 8 . |
| . . . | 8 . . | . . . |
|-----------+-----------+-----------|
| . *8 . | . . . | . . *8 |
| . . . | . 8 . | . . . |
| *8 . . | . . . | . . *8 |
|-----------+-----------+-----------|
| *8 . . | . . . | *8 . . |
| . *8 . | . . . | *8 . . |
| . . . | . . 8 | . . . |
+-----------------------------------+
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That leaves <3> and <7> which, in the BUG+3, force the cycles above to resolve themselves.
| Code: | +-----------------------------------+
| . . . | 3 . . | . . . |
| . . 3 | . . . | . . . |
| . . . | . . . | . 3 3 |
|-----------+-----------+-----------|
| . . . | . 3 . | . . 3 |
| 3 . . | . . . | . . . |
| . . . | . 3 . | . 3 #3 | # BUG+3 candidate
|-----------+-----------+-----------|
| . 3 . | . . . | . . . |
| . . . | . . 3 | . . . |
| . . . | . . . | 3 . . |
+-----------------------------------+
+-----------------------------------+
| . . . | . . 7 | . . . |
| . 7 . | . . . | 7 . . |
| 7 . . | . . . | . #7 7 | # BUG+3 candidate
|-----------+-----------+-----------|
| . . . | 7 . . | . . . |
| . . 7 | . . . | . . . |
| . . . | . . . | . 7 7 |
|-----------+-----------+-----------|
| 7 . . | . . . | 7 . . |
| . . . | . 7 . | . . . |
| #7 7 . | . . . | . 7 . | # BUG+3 candidate
+-----------------------------------+
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BUG+3:
| Code: | r3c8=7 => r3c1<>7
r9c1=7 => r3c1<>7
r6c9=3 => r3c9=7 => r3c1<>7
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Once r3c1=2 remains, the overlapping cycles for <2>, <4>, <6>, and <8> finish the solution -- including <3> and <7>.
Unfortunately, the Skyscraper r27c7 for <7> also forces r3c1=2. So the BUG+3 is overkill. 
BTW: This is my 2000th post. Of course you knew it would be long-winded.
Last edited by daj95376 on Wed May 05, 2010 2:44 am; edited 3 times in total |
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arkietech
Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA
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| Posted: Wed May 05, 2010 2:12 am Post subject: |
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| daj95376 wrote: | | Code: | r3c8=7 => r3c1<>7
r9c1=7 => r3c1<>7
r6c9=3 => r3c9=7 => r3c1<>7
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Nicely done Danny! Easly done with simple sudoku. This is handy to know. Thanks |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Wed May 05, 2010 1:35 pm Post subject: |
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| daj95376 wrote: | | Unfortunately, the Skyscraper r27c7 for <7> also forces r3c1=2. So the BUG+3 is overkill. |
Danny, the "fun factor" makes the BUG+3 my preferred step over the skyscraper.
My steps were "mirror-like" to yours.
| Code: | r3c8=7 => r9c8<>7
r9c1=7 => r9c8<>7
r6c9=3 => r6c8=7 => r9c8<>7
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Ted |
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