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Steve R
Joined: 24 Oct 2005
Posts: 289
Location: Birmingham, England
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 Posted: Tue Sep 18, 2007 1:12 pm Post subject: Good Times |
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This is the puzzle used in the final of the Times sudoku championship, held on 16 September.
| Code: | +-----------------------+
| . . 7 | . 5 8 | 2 . . |
| . . . | . 3 . | . . . |
| 8 . . | 6 . 2 | . . 7 |
-------------------------
| 5 . 6 | . . . | 3 . . |
| 7 3 . | . 6 . | . 1 2 |
| . . 4 | . . . | 9 . 5 |
-------------------------
| 6 . . | 7 . 1 | . . 4 |
| . . . | . 9 . | . . . |
| . . 5 | 3 2 . | 7 . . |
+-----------------------+ |
The winner, Tom Collier, completed it in 12 minutes 45 seconds.
I did not!
Steve |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Tue Sep 18, 2007 3:45 pm Post subject: |
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| Quote: | The winner, Tom Collier, completed it in 12 minutes 45 seconds.
I did not! |
Did not what? Finish in 12 minutes 45 seconds? Finish?  |
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Steve R
Joined: 24 Oct 2005
Posts: 289
Location: Birmingham, England
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| Posted: Tue Sep 18, 2007 4:17 pm Post subject: |
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It took me nearly an hour.
Steve |
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Johan
Joined: 25 Jun 2007
Posts: 206
Location: Bornem Belgium
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| Posted: Tue Sep 18, 2007 7:43 pm Post subject: |
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Guessing that the puzzle in The Times sudoku final would use the same advanced steps like the Super Fiendish on Saturday,It could save me quite some time. and yes both steps where present in the grid.(the other one, more harder to detect, because IMO this advanced step is very rare used for solving the VH's in The Daily Sudoku.)
Nevertheless the fore knowledge of these two advanced steps, it took me twenty minutes more than Tom's time. |
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Asellus
Joined: 05 Jun 2007
Posts: 865
Location: Sonoma County, CA, USA
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| Posted: Tue Sep 18, 2007 11:04 pm Post subject: |
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I didn't time myself, but it took me about 30 minutes. I only needed one advanced step, which wasn't all that advanced. Basic methods (line-box and naked/hidden sets) got me here:
| Code: | +------------------+------------------+------------------+
| 139 16 7 | 19 5 8 | 2 4 369 |
| 1249 146 129 | 19 3 7 | 8 5 69 |
| 8 5 39 | 6 4 2 | 1 39 7 |
+------------------+------------------+------------------+
| 5 29 6 | 24 1 49 | 3 7 8 |
| 7 3 89 | 58 6 59 | 4 1 2 |
| 12 18 4 | 28 7 3 | 9 6 5 |
+------------------+------------------+------------------+
| 6 29 239 | 7 8 1 | 5 239 4 |
| 123 7 1238 | 45 9 45 | 6 238 13 |
| 149 148 5 | 3 2 6 | 7 89 19 |
+------------------+------------------+------------------+ |
There is a 6-cell DP in R12C249. It includes an X-Wing on <6> (R12C29). So, <6> can be placed in R1C2 and R2C9 and the puzzle falls apart. |
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Asellus
Joined: 05 Jun 2007
Posts: 865
Location: Sonoma County, CA, USA
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| Posted: Tue Sep 18, 2007 11:23 pm Post subject: |
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Oops! 
I wrote too soon. I must have made a lucky error because my attempt to recreate the "puzzle falling apart" after the DP step didn't happen.
I had to use two more steps, one of them recently discussed on another thread involving coloring from a W-Wing (sort of "inverse multi-coloring). Here is the grid after the DP step:
| Code: | +------------------+------------------+------------------+
| 139 6 7 | 19 5 8 | 2 4 39 |
| 1249 14 129 | 19 3 7 | 8 5 6 |
| 8 5 39 | 6 4 2 | 1 39 7 |
+------------------+------------------+------------------+
| 5 29r 6 | 24 1 49g | 3 7 8 |
| 7 3 w89g | 58 6 59r | 4 1 2 |
| 12 18 4 | 28 7 3 | 9 6 5 |
+------------------+------------------+------------------+
| 6 29g 239 | 7 8 1 | 5 #23-9 4 |
| 123 7 1238 | 45 9 45 | 6 238 13 |
|#14-9 148 5 | 3 2 6 | 7 w89R 19 |
+------------------+------------------+------------------+ |
Note the {89} W-Wing that produces no direct elimination. However, the coloring shown eliminates <9> from the cells marked #.
After that, there is a {14} W-Wing in C12 that solves the puzzle.
[Edit for misspelling.] |
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nataraj
Joined: 03 Aug 2007
Posts: 1048
Location: near Vienna, Austria
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| Posted: Wed Sep 19, 2007 7:39 pm Post subject: |
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x-wing on 3 and then, here:
| Code: |
+--------------------------+--------------------------+--------------------------+
| 139 16 7 | 19 5 8 | 2 4 369 |
| 1249 146 129 | 19 3 7 | 8 5 69 |
| 8 5 39 | 6 4 2 | 1 39 7 |
+--------------------------+--------------------------+--------------------------+
| 5 29 6 | 24 1 49 | 3 7 8 |
| 7 3 89 | 58 6 59 | 4 1 2 |
| 12 18 4 | 28 7 3 | 9 6 5 |
+--------------------------+--------------------------+--------------------------+
| 6 29 239 | 7 8 1 | 5 239 4 |
| 123 7 128 | 45 9 45 | 6 28 13 |
| 149 148 5 | 3 2 6 | 7 89 19 |
+--------------------------+--------------------------+--------------------------+
|
xy-chain '29'(72)='92'(42)='21'(61)='18'(62)='89'(53)='93'(33)='39'(38 )='98'(98 )='82'(88 ) removes 2 from 3 cells: r7c8 r8c1 r8c3. |
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Johan
Joined: 25 Jun 2007
Posts: 206
Location: Bornem Belgium
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| Posted: Wed Sep 19, 2007 10:11 pm Post subject: |
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The same x-wing on <3> and then a swordfish on <9>.
In R129C149 the swordfish eliminates <9> in R9C8 and in R2C3
| Code: |
+---------------+---------+-----------+
|*139 16 7 |*19 5 8 | 2 4 *369 |
|*1249 146 12-9 |*19 3 7 | 8 5 *69 |
| 8 5 39 | 6 4 2 | 1 39 7 |
+---------------+---------+-----------+
| 5 29 6 | 24 1 49 | 3 7 8 |
| 7 3 89 | 58 6 59 | 4 1 2 |
| 12 18 4 | 28 7 3 | 9 6 5 |
+---------------+---------+-----------+
| 6 29 239 | 7 8 1 | 5 239 4 |
| 123 7 1238 | 45 9 45 | 6 238 13 |
|*149 148 5 | 3 2 6 | 7 8-9 *19 |
+---------------+---------+-----------+
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