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Earl
Joined: 30 May 2007
Posts: 677
Location: Victoria, KS
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 Posted: Thu May 22, 2008 2:07 pm Post subject: Serpentine |
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This took a variety of techniques. I could not find a single death blow.
Any aces out there?
Earl
| Code: |
+-------+-------+-------+
| . . 7 | . . 9 | 1 . 4 |
| . . . | . 8 . | . . . |
| . . 1 | . . 6 | . . . |
+-------+-------+-------+
| 4 . . | 2 . . | . 5 . |
| . . . | . 6 . | 8 . 2 |
| 2 6 . | 5 4 8 | . . . |
+-------+-------+-------+
| . 2 . | . . . | . . 1 |
| . . 6 | . . . | 7 . 3 |
| . 7 . | . 3 . | . 6 . |
+-------+-------+-------+
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Play this puzzle online at the Daily Sudoku site |
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Steve R
Joined: 24 Oct 2005
Posts: 289
Location: Birmingham, England
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| Posted: Thu May 22, 2008 4:34 pm Post subject: |
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| Code: | +-----------------------------------------------------+
| 6 58 7 | 3 25 9 | 1 28 4 |
| 359 3459 2 | 147 8 14 | 569 37 569 |
| 3589 34589 1 | 47 25 6 | 259 37 589 |
-------------------------------------------------------
| 4 1389 389 | 2 179 137 | 369 5 69 |
| 7 1359 359 | 19 6 13 | 8 4 2 |
| 2 6 39 | 5 4 8 | 39 1 7 |
-------------------------------------------------------
| 3589 2 34589 | 6 79 57 | 45 89 1 |
| 1589 589 6 | 1489 19 1245 | 7 289 3 |
| 1589 7 4589 | 189 3 125 | 245 6 58 |
+-----------------------------------------------------+ |
Boxes 8 and 9 are helpful.
If r8c8 contains 9, r9c79 contain 2 and 5. This places 1 in r9c6 and 9 in r8c5, a contradiction.
Steve |
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nataraj
Joined: 03 Aug 2007
Posts: 1048
Location: near Vienna, Austria
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| Posted: Thu May 22, 2008 5:14 pm Post subject: |
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Not a "single death blow", but a one-two combination:
after basics,
| Code: |
+--------------------------+--------------------------+--------------------------+
| 6 58 7 | 3 25 9 | 1 28 4 |
| 359 3459 2 | 147 8 14 | 569 37 569 |
| 3589 34589 1 | 47 25 6 | 259 37 589 |
+--------------------------+--------------------------+--------------------------+
| 4 1389 389 | 2 179 137 | 369 5 69 |
| 7 1359 359 | 19 6 13 | 8 4 2 |
| 2 6 39 | 5 4 8 | 39 1 7 |
+--------------------------+--------------------------+--------------------------+
| 3589 2 34589 | 6 79# 57* | 4-5 89# 1 |
| 1589 589 6 | 1489 19 1245 | 7 289 3 |
| 1589 7 4589 | 189 3 12-5 | 245 6 58* |
+--------------------------+--------------------------+--------------------------+
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a short xy-chain (or generalized xy-wing) with pincers 57 at r7c6 and 58 at r9c9, connected by 79-98 in row 7, removes 5 from r7c7 and r9c6, giving r7c7=4 which makes r9c7 = {2,5} and there is now another xy-chain in boxes 8 and 9:
| Code: |
+--------------------------+--------------------------+--------------------------+
| 3589 2 34589 | 6 79 57 | 4 89* 1 |
| 1589 589 6 | 1489 19* 1245 | 7 289 3 |
| 1589 7 4589 | 189 3 12# | 25# 6 58# |
+--------------------------+--------------------------+--------------------------+
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pincers 89 in r7c8 and 19 in r8c5, connected by 85-53-21 in col 9 take out 9 in r7c5 and this solves the puzzle. |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Thu May 22, 2008 5:16 pm Post subject: |
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| I couldn't see any of the usual techniques that are so often discussed here, but extended Medusa did it, first via a couple of traps, then a wrap. |
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Asellus
Joined: 05 Jun 2007
Posts: 865
Location: Sonoma County, CA, USA
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| Posted: Thu May 22, 2008 7:39 pm Post subject: |
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Steve's one-step solution is an interesting triple ALS elimination:
| Code: | +------------------------------------------------------+
| 6 58 7 | 3 25 9 | 1 28 4 |
| 359 3459 2 | 147 8 14 | 569 37 569 |
| 3589 34589 1 | 47 25 6 | 259 37 589 |
--------------------------------------------------------
| 4 1389 389 | 2 179 137 | 369 5 69 |
| 7 1359 359 | 19 6 13 | 8 4 2 |
| 2 6 39 | 5 4 8 | 39 1 7 |
--------------------------------------------------------
| 3589 2 34589 | 6 #7-9 57 |B45 A89 1 |
| 1589 589 6 | 1489 C19 1245 | 7 #28-9 3 |
| 1589 7 4589 | 189 3 B125 |B245 6 A58 |
+------------------------------------------------------+ |
ALS "A" and "B" have shared exclusive digit <5>. "B" and "C" have shared exclusive <1>. "A" and "C" have shared common digit <9>, eliminating <9> from r7c5 and r8c8.
For those interested in notation, this might be written:
ALS[(9)r7c8=(5)r9c9] - ALS[(5)r79c7|r9c6=(1)r9c6] - (1=9)r8c5 |
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storm_norm
Joined: 18 Oct 2007
Posts: 1741
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| Posted: Thu May 22, 2008 11:03 pm Post subject: |
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just for kicks the finned x-wing on 8 was first out of the gate after basics
| Code: | .---------------------.---------------------.---------------------.
| 6 58 7 | 3 25 9 | 1 28 4 |
| 359 3459 2 | 147 8 14 | 569 37 569 |
|#3589 34589 1 | 47 25 6 | 259 37 #589 |
:---------------------+---------------------+---------------------:
| 4 1389 389 | 2 179 137 | 369 5 69 |
| 7 1359 359 | 19 6 13 | 8 4 2 |
| 2 6 39 | 5 4 8 | 39 1 7 |
:---------------------+---------------------+---------------------:
|#3589 2 34589 | 6 79 57 | 45 89 1 |
|#1589 589 6 | 1489 19 1245 | 7 289 3 |
|#1589 7 45-89 | 189 3 125 | 245 6 #58 |
'---------------------'---------------------'---------------------' |
and like nataraj, I could only find xy-chains, there is some useless w-wing extended 5's that can be eliminated but do not help |
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Asellus
Joined: 05 Jun 2007
Posts: 865
Location: Sonoma County, CA, USA
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| Posted: Fri May 23, 2008 4:42 am Post subject: |
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| Well, since you are mentioning fish... a Sashimi X-Wing in r17 removes <8> from r8c2. |
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