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Puzzle 10/04/23 ___ Salsa

 
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daj95376



Joined: 23 Aug 2008
Posts: 3854
PostPosted: Fri Apr 23, 2010 4:53 pm    Post subject: Puzzle 10/04/23 ___ Salsa Reply with quote
Numerous basics ... BBDB ... and possibly 2x Chains

Code:
 +-----------------------+
 | 7 . . | . . 8 | . 2 . |
 | . 2 . | . 3 4 | . . . |
 | . . 6 | . 2 . | . . 4 |
 |-------+-------+-------|
 | . . . | . 8 . | . . . |
 | . 6 5 | 3 . . | 2 . . |
 | 8 9 . | . . 6 | 5 3 . |
 |-------+-------+-------|
 | . . . | . 9 3 | 4 . 8 |
 | 6 . . | . . 2 | . 7 . |
 | . . 8 | . . . | 9 . . |
 +-----------------------+

Play this puzzle online at the Daily Sudoku site
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wapati



Joined: 10 Jun 2008
Posts: 472
Location: Brampton, Ontario, Canada.
PostPosted: Sat Apr 24, 2010 3:39 am    Post subject: Reply with quote
Yep, got it. Lots of stuff, two shortish xy-chains.

Fun puzzle!
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peterj



Joined: 26 Mar 2010
Posts: 974
Location: London, UK
PostPosted: Sat Apr 24, 2010 9:28 am    Post subject: Reply with quote
Phew! That took some work - nice puzzle! Alot of fun.
My solution path below, I'm sure it's not optimal, but I went down many more paths just to get here...

Quote:
A lot of basics...!
Multi-colour Wrap(4); r1c2<>4, r5c5<>4, r6c3<>4, r9c1<>4
Kite(5) extended r8c5=r9c5; r9c1<>5
xy-chain:(1=3)r9c1-(3=9)r3c1-(9=5)r2c1-(5=3)r1c2-(3=5)r1c9-(5=3)r8c9-(3=1)r8c7; r8c2<>1
x-wing(1) r18c57; r3c7<>1, r5c569<>1
xy-chain: (1=7)r4c2-(7=6)r4c7-(6=1)r1c6-(1=9)r3c8-(9=3)r3c1-(3=1)r9c1; r69c3<>1
xy-wing(139); r9c8<>1
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wapati



Joined: 10 Jun 2008
Posts: 472
Location: Brampton, Ontario, Canada.
PostPosted: Sat Apr 24, 2010 10:26 pm    Post subject: Reply with quote
Hmm, deja vue? I didn't solve it twice, just fotgot that I had posted already. Embarassed

Last edited by wapati on Sun Apr 25, 2010 3:07 pm; edited 1 time in total
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daj95376



Joined: 23 Aug 2008
Posts: 3854
PostPosted: Sun Apr 25, 2010 4:07 am    Post subject: Reply with quote
FYI:

Code:
 after initial basics
 *--------------------------------------------------------------------*
 | 7      345    34     | 9      16     8      | 16     2      35     |
 | 59     2      1      | 67     3      4      | 8      59     67     |
 | 39     8      6      | 157    2      157    | 137    19     4      |
 |----------------------+----------------------+----------------------|
 | 123    137    237    | 1257   8      1579   | 67     4      1679   |
 | 14     6      5      | 3      147    179    | 2      8      179    |
 | 8      9      247    | 1247   147    6      | 5      3      17     |
 |----------------------+----------------------+----------------------|
 | 125    157    27     | 167    9      3      | 4      156    8      |
 | 6      145    9      | 8      145    2      | 13     7      35     |
 | 1345   13457  8      | 1467   14567  17     | 9      156    2      |
 *--------------------------------------------------------------------*

 c14r9   Skyscraper                      <> 4    r5c5,r6c3
 r27\c18 finned  X-Wing                  <> 5    r9c1
 r25\c49 Sashimi X-Wing                  <> 7    r46c4       extraneous

 <39+1>  XY-Wing  r3c1/r3c8+r9c1         <> 1    r9c8        extraneous

 <16+7>  XYZ-Wing r7c4/r2c4+r9c6         <> 7    r9c4        extraneous

Code:
 W-Wing (1=3)r8c7 - r3c7 = r3c1 - (3=1)r9c1  =>  r8c2<>1
 +-----------------------------------------------------------------------+
 |  7      35     4      |  9      16     8      |  16     2      35     |
 |  59     2      1      |  67     3      4      |  8      59     67     |
 | c39     8      6      |  157    2      157    | b137    19     4      |
 |-----------------------+-----------------------+-----------------------|
 |  12     17     3      |  25     8      579    |  67     4      679    |
 |  4      6      5      |  3      17     179    |  2      8      179    |
 |  8      9      27     |  124    147    6      |  5      3      17     |
 |-----------------------+-----------------------+-----------------------|
 |  125    157    27     |  167    9      3      |  4      156    8      |
 |  6      45-1   9      |  8      145    2      | a13     7      35     |
 | d13     13457  8      |  146    14567  17     |  9      56     2      |
 +-----------------------------------------------------------------------+
 # 63 eliminations remain

Code:
 r18     X-Wing                          <> 1    r569c5,r3c7

 <37+1>  XYZ-Wing r9c2/r4c2+r9c1         <> 1    r7c2   extraneous

Code:
 (1=7)r4c2 - (7=6)r4c7 - (6=1)r1c7 - (1=9)r3c8 - (9=3)r3c1 - (3=1)r9c1  =>  r4c1,r79c2<>1
 +-----------------------------------------------------+
 |  7    35   4    |  9    16   8    |  16   2    35   |
 |  59   2    1    |  67   3    4    |  8    59   67   |
 |  39   8    6    |  157  2    157  |  37   19   4    |
 |-----------------+-----------------+-----------------|
 |  12   17   3    |  25   8    59   |  67   4    679  |
 |  4    6    5    |  3    7    19   |  2    8    19   |
 |  8    9    27   |  12   4    6    |  5    3    17   |
 |-----------------+-----------------+-----------------|
 |  125  57   27   |  167  9    3    |  4    16   8    |
 |  6    4    9    |  8    15   2    |  13   7    35   |
 |  13   137  8    |  4    56   17   |  9    56   2    |
 +-----------------------------------------------------+
 # 43 eliminations remain
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peterj



Joined: 26 Mar 2010
Posts: 974
Location: London, UK
PostPosted: Sun Apr 25, 2010 7:35 am    Post subject: Reply with quote
It's interesting how different people/solvers use different techniques but the structure of the solution and the key digits are quite similar...

Your step == My equivalent step

Skyscraper(4) == Colouring(4)
Finned x-wing(5) == Extended Kite(5)
w-wing(13) == xy-chain(13)
x-wing(1) == x-wing(1)
xy-chain @r4c2 == xy-chain @r4c2

I suppose it depends on the order you apply classes of technique and then just what you grew up! I always used colouring as a first advanced step and so normally catch most fish patterns in that; until I started coming to this forum I never heard of W/M-wings and so usually have equivalent chain steps in my solutions. (I need to learn W/M wings more as chains are hard work!)
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Mogulmeister



Joined: 03 May 2007
Posts: 1151
PostPosted: Sun Apr 25, 2010 8:46 am    Post subject: Reply with quote
The w/m wings are like so many Sudoku patterns - codified AICs - but have spottable characteristics.
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peterj



Joined: 26 Mar 2010
Posts: 974
Location: London, UK
PostPosted: Sun Apr 25, 2010 9:14 am    Post subject: Reply with quote
Of course almost everything boils down to AIC/ALS type moves - but as you say it's just a question of training yourself to see certain patterns. M-wings have more of pattern (remote pair, strong link) then say xy-chain which is my normal next step after single digit techniques.. Need to get my eye in and this forum seems a good place for examples and exponents of the technique!
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Marty R.



Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
PostPosted: Sun Apr 25, 2010 6:14 pm    Post subject: Reply with quote
This was a long slog for me, about a double BBDB, but for quite a while I didn't think I'd be able to solve it without trial and error. I used a half-dozen moves, then a flightless M-Wing (35) with pincer transports opened up two puzzle-ending XY-Wings.

However, it was good for my puzzle inventory, since I would've used up three or four puzzles in the time I spent on this. Laughing
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