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daj95376
Joined: 23 Aug 2008 Posts: 3854
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Posted: Fri Jun 26, 2009 5:36 pm Post subject: Extreme Puzzle 09/06/26 |
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For those with strong masochistic tendencies!!!
Code: | +-----------------------+
| . . . | . . . | 9 2 . |
| . 3 . | . . . | . . 7 |
| . . 9 | . 2 . | . 5 6 |
|-------+-------+-------|
| . . . | 7 . . | 2 . . |
| . . 4 | . . . | . 7 . |
| . . . | . . 2 | 4 . 1 |
|-------+-------+-------|
| 1 . . | 2 . 3 | . . . |
| 3 . 7 | . 5 . | . 4 2 |
| . 4 2 | . . 7 | . 9 . |
+-----------------------+
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Play this puzzle online at the Daily Sudoku site
Note: I'm going to add solutions to most puzzles over a week old. The head post will be updated so as not to make them active again. |
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wapati
Joined: 10 Jun 2008 Posts: 472 Location: Brampton, Ontario, Canada.
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Posted: Fri Jun 26, 2009 10:49 pm Post subject: |
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I quite liked it, lots of patterns in there!
I managed to avoid ERs and Turbots and Kites, which means there are lots of approaches.
I did use UR, x-wing, xy-wings, W-wings and maybe a 4 cell xy-chain.
Pretty sure the chain added nothing compared to the W-wing I found next.
Fun!! |
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tlanglet
Joined: 17 Oct 2007 Posts: 2468 Location: Northern California Foothills
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Posted: Sat Jun 27, 2009 11:33 pm Post subject: |
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I started this puzzle looking for xy-wings and my first check stumbled into this funny chain-like thing that I believe/hope is valid.
In English: xy-wing with pivot 69 at r2c5 and a pincer 56 at r1c6. If r2c5=6 then r1c6=5. If r2c5=9, then r6c5<>9 but = <68> which forms a <368> subset with the three cells r6c358, which then deletes <68> from r6c2 and makes r6c2=5 thereby completing the xy-wing to delete 5 from r1c2.
In (something like ) Notation: (5=6)r1c6 - (6=9)r2c5 -(9)r6c5 =(68)r6c5 - ss[(368)r6c358 - (68)r6c2] = (5)r6c2; r1c2<>5.
(This pattern is similar to another pattern that I posted several days ago, so I hope this step is valid.)
I also transported the 5 in r1c6 to r9c1 to delete 5 in r4c1.
To complete the puzzle, I used a xyz-wing, a Type 4 UR, a short xy-chain, and a xy-wing.
Ted |
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storm_norm
Joined: 18 Oct 2007 Posts: 1741
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Posted: Sun Jun 28, 2009 5:09 am Post subject: |
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Quote: | In English: xy-wing with pivot 69 at r2c5 and a pincer 56 at r1c6. If r2c5=6 then r1c6=5. If r2c5=9, then r6c5<>9 but = <68> which forms a <368> subset with the three cells r6c358, which then deletes <68> from r6c2 and makes r6c2=5 thereby completing the xy-wing to delete 5 from r1c2.
In (something like ) Notation: (5=6)r1c6 - (6=9)r2c5 -(9)r6c5 =(68)r6c5 - ss[(368)r6c358 - (68)r6c2] = (5)r6c2; r1c2<>5.
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first of all, nice chain.
this is how I would write it.
nt=naked triple
grp=group
(5=6)r1c6 - (6=9)r2c5 - (9)r6c5 = (nt368)r6c358 - (grp68=5)r6c2 |
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storm_norm
Joined: 18 Oct 2007 Posts: 1741
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Posted: Sun Jun 28, 2009 7:12 am Post subject: |
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using Ted's move, I think I got this down to 4 steps
Code: | .------------------.------------------.------------------.
| 568 1568 18 | 3 7 56 | 9 2 4 |
| 2 3 56 | 4 69 569 | 8 1 7 |
| 4 7 9 | 18 2 18 | 3 5 6 |
:------------------+------------------+------------------:
| 5689 1568 138 | 7 68 4 | 2 368 589 |
|*89 2 4 | 156 3 16 | 56 7 *89 |
| 7 568 38 | 569 689 2 | 4 368 1 |
:------------------+------------------+------------------:
| 1 9 *56 | 2 4 3 | 7 68 *58 |
| 3 *68 7 | 689 5 689 | 1 4 2 |
|56-8 4 2 | 68 1 7 | 56 9 3 |
'------------------'------------------'------------------' |
1...extended xy-wing:
(8=6)r8c2 - (6=5)r7c3 - (5=8)r7c9 - (8)r5c9 = (8)r5c1; r9c1 <> 8
Code: | .------------------.------------------.------------------.
| 568 156 18 | 3 7 56 | 9 2 4 |
| 2 3 56 | 4 *69 *569 | 8 1 7 |
| 4 7 9 | 1 2 8 | 3 5 6 |
:------------------+------------------+------------------:
| 5689 156 138 | 7 68 4 | 2 368 589 |
| 89 2 4 | 56 3 1 | 56 7 89 |
| 7 56 38 |*569 *689 2 | 4 368 1 |
:------------------+------------------+------------------:
| 1 9 56 | 2 4 3 | 7 68 58 |
| 3 8 7 |*69 5 *69 | 1 4 2 |
| 56 4 2 | 8 1 7 | 56 9 3 |
'------------------'------------------'------------------' |
MUG69 marked above
2...MUG69[{xy-wing, (56)r6c2, (58)r6c45, (68)r4c5} = (5)r2c6] - (5)r2c3 = (5)r7c3 - (5=6)r9c1; r4c1 <> 6
Code: | .---------------.---------------.---------------.
| 568 1-5 18 | 3 7 *56 | 9 2 4 |
| 2 3 56 | 4 *69 569 | 8 1 7 |
| 4 7 9 | 1 2 8 | 3 5 6 |
:---------------+---------------+---------------:
| 589 156 138 | 7 68 4 | 2 368 589 |
| 89 2 4 | 56 3 1 | 56 7 89 |
| 7 *56 *38 | 569 *689 2 | 4 *368 1 |
:---------------+---------------+---------------:
| 1 9 56 | 2 4 3 | 7 68 58 |
| 3 8 7 | 69 5 69 | 1 4 2 |
| 56 4 2 | 8 1 7 | 56 9 3 |
'---------------'---------------'---------------' |
3...Ted's move marked above except r6c2 would be (6=5) instead of (68=5)
4... UR type 1 {89} r45c19 removes 89 from r4c9 |
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