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daj95376
Joined: 23 Aug 2008
Posts: 3854
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 Posted: Sat Jan 30, 2010 1:12 am Post subject: Puzzle 10/01/29 (A) |
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| Code: | +-----------------------+
| 3 . . | . . . | . 7 . |
| . . . | 3 . 7 | 6 . . |
| . . 6 | 5 . . | 3 . . |
|-------+-------+-------|
| . 5 8 | 1 . . | 9 . . |
| . . . | . 2 . | 8 5 7 |
| . 3 . | . . . | . . . |
|-------+-------+-------|
| . 8 7 | 6 1 . | . . 2 |
| 6 . . | . 8 . | . 4 . |
| . . . | . 3 . | 7 . 6 |
+-----------------------+
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Play this puzzle online at the Daily Sudoku site |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Sat Jan 30, 2010 5:53 am Post subject: |
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I used:
| Quote: | XY (249)
XY (892)
ERs (2,4,4)
X (4)
XY (149) |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Sun Jan 31, 2010 11:31 pm Post subject: |
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After seeing the new posts by Danny, I purposely did not pick the BBDB offering, only to pick this one which turned out, for me, to be a real BBDBer! It was fun but it did take me two sessions to complete it.
xy-wing 24-9 with vertex 24 in r4c1 plus pincer transport,
then a AIC: (9=4)r5c4 - (4=6)r4c6 - (6=2)r4c8 - r23c8 = r1c7 - (2=8)r1c4 - (8=9)r6c4; r6c6|r9c4<>9,
x-wing 4 in r47c16,
My next move was involved, but hopefully valid. Here is the grid:
| Code: |
*-----------------------------------------------------------*
| 3 9 1245 | 28 6 128 | 24 7 1458 |
| 258 #14 #1245 | 3 49 7 | 6 129 1458 |
| 28 7 6 | 5 49 128 | 3 129 148 |
|-------------------+-------------------+-------------------|
| 24 5 8 | 1 7 46 | 9 26 3 |
| 1 6 49 | 49 2 3 | 8 5 7 |
| 7 3 29 | 89 5 68 | 24 126 14 |
|-------------------+-------------------+-------------------|
| 49 8 7 | 6 1 49 | 5 3 2 |
| 6 2 3 | 7 8 5 | 1 4 9 |
| 59 #14 #145 | 24 3 29 | 7 8 6 |
*-----------------------------------------------------------*
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Now notice the UR14 in r29c23, marked #. To prevent the deadly pattern, r2c3=2 or r29c3=5, which forms a pseudocell 25 in r29c3.
This pseudocell may be combined with the 29 in r6c3 to form an ALS 259 in r269c3, thereby providing a strong reference between the 2s and the 9.
ALS[(2)r26 = (9)r6c3]r269c3 - (9=8)r6c4 - (8=2)r1c4; r1c3<>2. (That was a lot of work for a deletion of questionable value!)
The ALS defined above also provides a strong reference between the 5s and the 9.
ALS[(5)r29c3 = (9)r6c3]r269c3 - (9=4)r5c3 - r4c1 = (4-9)r7c1 = (9-5)r9c1 = (5)r2c1; r1c3<>5.
(Note we could also have made direct use of the UR 14 in r29c23 to make this last deletion by directly evaluating the requirements to prevent the deadly pattern.
(5)r29c3; r1c3<>5,
(2)r2c3 - (2=9)r6c3 - (9=4)r5c3 - r4c1 = (4-9)r7c1 = (9-5)r9c1 = (5)r2c1; r1c3<>5.)
a skyscraper 2 in r6c37, and a xy-wing 1-49 with vertex in r2c8 completes the puzzle.
Ted  |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Mon Feb 01, 2010 3:30 am Post subject: |
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mea culpa Sorry! 
I was so interested in the difficulty of the steps, that I failed to count them.
X-Wing, 2x XY-Wing, Kite, and another XY-Wing.
Regards, Danny |
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Wendy W
Joined: 04 Feb 2008
Posts: 144
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| Posted: Tue Feb 02, 2010 12:36 am Post subject: |
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| Marty R. wrote: | I used:
| Quote: | XY (249)
XY (892)
ERs (2,4,4)
X (4)
XY (149) |
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Much like Marty and Danny:
X-wing (4)
XY-wing (289)
XY-wing (249)
Kite (249) |
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