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hughwill
Joined: 05 Apr 2010
Posts: 424
Location: Birmingham UK
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 Posted: Mon Feb 14, 2011 11:17 am Post subject: Mon Feb 14th VH |
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I'm not so hot on these- was this a more complicated VH than usual? After the
obvious (and unnecessary?) 25 UR I got a colouring on a chain of 6's removing
6 from C1 and then a 246 XY wing pivoting on C8. Was there an easier way?
By the way- where is everyone? Very late for a first post.....
After basics | Code: |
+----------------+----------+--------------+
| 69 1 3 | 8 4 69 | 26 7 5 |
| 469 456 569 | 2 7 169 | 1368 38 3468 |
| 246 7 8 | 5 3 16 | 16 46 9 |
+----------------+----------+--------------+
| 38 2358 245 | 6 25 7 | 9 1 238 |
| 1 26 7 | 9 8 3 | 5 46 246 |
| 368 9 25 | 1 25 4 | 368 38 7 |
+----------------+----------+--------------+
| 5 36 16 | 4 9 8 | 7 2 136 |
| 34689 3468 69 | 7 1 2 | 368 5 368 |
| 7 28 12 | 3 6 5 | 4 9 18 |
+----------------+----------+--------------+
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Play this puzzle online at the Daily Sudoku site |
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Stanley P
Joined: 27 Feb 2008
Posts: 20
Location: Tennessee, USA
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| Posted: Mon Feb 14, 2011 1:32 pm Post subject: |
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| I had slightly different basics and found an xyz wing on 126 in boxes 2 and 3. That did it for me. |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Mon Feb 14, 2011 4:41 pm Post subject: |
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| Like Stanley, I had a 2 in r3c7 and used the XYZ-Wing. However, in Hugh's grid the 16 pair in row 3 would knock out the other 6s in that row and finish it off. |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Mon Feb 14, 2011 4:57 pm Post subject: |
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After basics: | Code: | +-------------------+-------------------+-------------------+
| 269 1 3 | 8 4 69 | 26 7 5 |
| 469 456 4569 | 2 7 169 | 1368 38 3468 |
| 246 7 8 | 5 3 16 | 126 46 9 |
+-------------------+-------------------+-------------------+
| 348 23458 245 | 6 25 7 | 9 1 2348 |
| 1 246 7 | 9 8 3 | 5 46 246 |
| 368 9 25 | 1 25 4 | 368 38 7 |
+-------------------+-------------------+-------------------+
| 5 36 16 | 4 9 8 | 7 2 136 |
| 34689 3468 469 | 7 1 2 | 368 5 368 |
| 7 28 12 | 3 6 5 | 4 9 18 |
+-------------------+-------------------+-------------------+
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Keith |
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cgordon
Joined: 04 May 2007
Posts: 769
Location: ontario, canada
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| Posted: Mon Feb 14, 2011 6:31 pm Post subject: |
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R3C78 cannot be a 1 and 6 or a 2 and 6. Can only be a 1 and 4, 2 and 4, or 6 and 4. Ergo R3C8 has to be a 4.
I think that’s an APE (aligned pair exclusion). Better than looking for wings. |
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Ema Nymton
Joined: 17 Apr 2009
Posts: 89
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| Posted: Tue Feb 15, 2011 1:17 pm Post subject: |
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.
I conceed defeat. This is one subtle puzzle.
| Code: |
+------------------+----------+--------------+
| 269 1 3 | 8 4 69 | 26 7 5 |
| 469 456 4569 |*2 7 169 | 1368 38 368 |
| 26 7 8 | 5 3 16 | 126 4 9 |
+------------------+----------+--------------+
| 348 23458 245 | 6 25 7 | 9 1 2348 |
| 1 24 7 | 9 8 3 | 5 6 24 |
| 368 9 256 | 1 25 4 | 38 38 7 |
+------------------+----------+--------------+
| 5 36 16 | 4 9 8 | 7 *2 136 |
| 34689 3468 469 | 7 1 2 | 368 5 368 |
| 7 28 12 | 3 6 5 | 4 9 18 |
+------------------+----------+--------------+
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The key was '2' in r2c4 and r7c8.
Thank you for the challenge.
Ema Nymton
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Tue Feb 15, 2011 3:59 pm Post subject: |
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| cgordon wrote: | R3C78 cannot be a 1 and 6 or a 2 and 6. Can only be a 1 and 4, 2 and 4, or 6 and 4. Ergo R3C8 has to be a 4.
I think that’s an APE (aligned pair exclusion). Better than looking for wings. |
I agree with your analysis and that the pattern is an APE; it is also an xyz-wing as previously noted by Stanley and Marty. However I question your definition of "Better". In general, looking for an APE is more complex and cumbersome that looking for an xyz-wing, which is also frequently an APE pattern.
I guess "Better" truly depends on what motivates us to play Sudoku.
Ted |
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