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daj95376
Joined: 23 Aug 2008
Posts: 3854
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 Posted: Thu Aug 19, 2010 7:24 am Post subject: Puzzle 10/08/19: C |
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| Code: | +-----------------------+
| . . 1 | 4 5 . | 6 . . |
| . 4 . | . 8 3 | . 1 . |
| 2 . . | . . . | . 3 . |
|-------+-------+-------|
| 4 . . | . . . | 1 5 . |
| 8 1 . | . 9 . | 4 6 . |
| . 3 . | . . 4 | . . . |
|-------+-------+-------|
| 1 . . | 5 4 . | 3 . 6 |
| . 9 3 | 1 2 . | . . . |
| . . . | . . . | 8 . . |
+-----------------------+
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Play this puzzle online at the Daily Sudoku site |
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JC Van Hay
Joined: 13 Jun 2010
Posts: 494
Location: Charleroi, Belgium
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| Posted: Thu Aug 19, 2010 12:11 pm Post subject: |
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| Quote: | Type 1 UR(57)R28C79 : r2c7<>57
X Wing : (6)R26/C34 : r3c34<>6, r9c4<>6
4-SIS AIC : 9R1 (97)R3C4 7C5 (79)R4C3 : r4c9<>9 |
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peterj
Joined: 26 Mar 2010
Posts: 974
Location: London, UK
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| Posted: Thu Aug 19, 2010 1:17 pm Post subject: |
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The pattern of 2s looked so turboty I got carried away... for a one-step
| Quote: | almost/kraken skyscraper(2) in r1 and r5 with fin (2)r5c3 which forces 2 in r1c6, r4c6<>2
skyscraper(2)[(2)r1c6=r1c9 - r5c9=r5c4] = (2-7)r5c3=r5c4 - (7=3)r4c5 - (3=6)r9c5 - (6=9)r9c6 - (9=2)r1c6 ; r2c4<>2, r4c6<>2 |
[Edit. Correct skyscraper sub-AIC.]
Last edited by peterj on Thu Aug 19, 2010 4:57 pm; edited 1 time in total |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Thu Aug 19, 2010 4:25 pm Post subject: |
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[Withdrawn after Peter corrected his notation.]
Last edited by daj95376 on Thu Aug 19, 2010 6:26 pm; edited 1 time in total |
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peterj
Joined: 26 Mar 2010
Posts: 974
Location: London, UK
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| Posted: Thu Aug 19, 2010 4:54 pm Post subject: |
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| Code: | +--------------------------------------------------------------+
| 3 7 1 | 4 5 29A* | 6 8 29a |
| 59 4 569 | 679-2 8 3 | 2579 1 57 |
| 2 68 5689 | 679 67 1 | 579 3 4 |
|--------------------+--------------------+--------------------|
| 4 26 79 | 378 37* 6-2 | 1 5 389 |
| 8 1 27F | 237B* 9 5 | 4 6 23b |
| 59 3 2569 | 268 1 4 | 29 7 289 |
|--------------------+--------------------+--------------------|
| 1 28 28 | 5 4 7 | 3 9 6 |
| 6 9 3 | 1 2 8 | 57 4 57 |
| 7 5 4 | 369 36* 69* | 8 2 1 |
+--------------------------------------------------------------+ |
Sorry, I wrote the skyscraper the wrong way around... it should be
(2)r1c6=r1c9 - r5c9=r5c4 with fin r5c3
I marked it with Aa and Bb with AB the pincers and F the fin.
The chain works like this (marked with *)
If r5c3 is 2 then it is not 7 so r5c4 is 7 (conjugate in r5)
- so r4c5 is 3 (bivalue)
- so r9c5 is 6 (bivalue)
- so r9c6 is 9 (bivalue)
- so r1c6 is 2 (bivalue)
- so neither r2c4 or r4c6 can be 2
Either the skyscraper exists or the chain forces 2 in r1c6?
I am not assuming anything about r1c9? Tell me if I am still smoking stuff.. |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Thu Aug 19, 2010 5:56 pm Post subject: |
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| peterj wrote: | | Tell me if I am still smoking stuff.. |
Peter: Thanks for the revised solution. It works better for me.
I see your solution as:
| Code: | Skyscraper r15c9 => r2c4,r4c6<>2 -or-
(2-7)r5c3 = r5c4 - (7=3)r4c5 - (3=6)r9c5 - (6=9)r9c6 - (9=2)r1c6 - { r2c4,r4c6 }
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peterj
Joined: 26 Mar 2010
Posts: 974
Location: London, UK
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| Posted: Fri Aug 20, 2010 7:53 am Post subject: |
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| daj95376 wrote: | | Code: | Skyscraper r15c9 => r2c4,r4c6<>2 -or-
(2-7)r5c3 = r5c4 - (7=3)r4c5 - (3=6)r9c5 - (6=9)r9c6 - (9=2)r1c6 - { r2c4,r4c6 }
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Danny, thanks.
I always used to use that explicit "pattern or fin chain" notation, but a couple of experienced people suggested to combine them in a single AIC with a strong link between the two and the AIC for the "pattern" in brackets. It's terse but clearly not very explicit!
I suppose it is valid to think of a strong link between the two - if either is false the other is true. They are also weakly linked too. |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Fri Aug 20, 2010 1:01 pm Post subject: |
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Two steps............
| Quote: | Type 1 UR (57)r28c79; r2c7<>57
AIC found extending the vertex of potential xy-wing: (7=2)r5c3-(2=6)r4c2-r4c6=r9c6-(6=3)r9c5-(3=7)r4c5; r4c3<>7 |
Ted |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Fri Aug 20, 2010 4:49 pm Post subject: |
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| peterj wrote: | I always used to use that explicit "pattern or fin chain" notation, but a couple of experienced people suggested to combine them in a single AIC with a strong link between the two and the AIC for the "pattern" in brackets. It's terse but clearly not very explicit!
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Let me know who they are and I'll put a contract out on them!!! _  _ |
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