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Set XY_03 Puzzle 041

 
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daj95376



Joined: 23 Aug 2008
Posts: 3854
PostPosted: Sat Oct 17, 2009 5:37 am    Post subject: Set XY_03 Puzzle 041 Reply with quote
Code:
XY puzzles can be solved using these techniques:

Basics:  Naked/Hidden Single, Naked Pair/Triple, Locked Candidates 1/2
Basics+: Naked Quad, Hidden Pair/Triple/Quad
VH:      BUG+1, UR Type 1, X-Wing, XY-Wing
VH+:     2-String Kite, Empty Rectangle, Remote Pair, Skyscraper,
         XYZ-Wing, finned X-Wing, UR Type 2/4
XY:      gM-Wing, W-Wing, XY-Chain, BUG+2, BUG+3, other URs

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

Play this puzzle online at the Daily Sudoku site
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arkietech



Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA
PostPosted: Sat Oct 17, 2009 1:20 pm    Post subject: Reply with quote
Linked w-wing? Very Happy
Code:
 *--------------------------------------------------------------------*
 | 2      146    146    | 468    39     39     | 17     5      178    |
 | 5      8      3      | 1      7      2      | 9      6      4      |
 | 147    1467   9      | 468   #48     5      | 2     #18     3      |
 |----------------------+----------------------+----------------------|
 | 1347   1467   14678  | 9      2      138    | 5      148    1678   |
 | 9      5      1468   | 7      1368   138    | 134    2      168    |
 | 137    2      1678   | 5      1368   4      | 137    9      1678   |
 |----------------------+----------------------+----------------------|
 | 8     *14     5      | 2     #14     7      | 6      3      9      |
 | 147    9      147    | 3      5      6      | 8     *14     2      |
 | 6      3      2      | 48     1489   189    | 14     7      5      |
 *--------------------------------------------------------------------*
 XY-Chain:
(4=1)r7c2-(1=4)r7c5-(4=8)r3c5-(8=1)r3c8-(1=4)r8c8 => r8c13<>4;
singles remain
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tlanglet



Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
PostPosted: Sat Oct 17, 2009 9:46 pm    Post subject: Reply with quote
I was playing around with the implications of the Type 6 UR 48 in r39c45, and found a chain very similar to the one found by Dan.

(4)r9c7 - (4=1)r8c8 - (1=8)r3c8 - (8=4)r3c5 - (4)r79c5 = (4)r9c4; r9c7<>4.

Ted Smile
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tlanglet



Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
PostPosted: Sat Oct 17, 2009 10:25 pm    Post subject: Reply with quote
After my previous post, I looked at the puzzle again, ignoring my first solution. I found another one step solution of the VH variety.
Quote:
xy-wing -148 with vertex 48 in r9c4, pincer 14 in r9c7 and extended pincer 18: (8)r9c4 - (8)r13c4 = (8)r3c5 - (8=1)r3c8; r1c7, r8c8 <> 1

This solution still used some of the same cells as involved in the solution previously posted by both Dan and I.

Ted
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