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nataraj
Joined: 03 Aug 2007 Posts: 1048 Location: near Vienna, Austria
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Posted: Fri Nov 21, 2008 4:24 pm Post subject: Competition diabolical #1230 Nov 21 |
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Today's Diabolical
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+-----------+-----------+-----------+
| 8 . 6 | . 9 . | . . . |
| . 9 . | . . . | . 3 . |
| . 4 . | 7 . 2 | . . . |
+-----------+-----------+-----------+
| 1 . . | . 6 8 | . . 5 |
| . 2 . | . 3 . | . 8 . |
| 4 . . | 9 . . | . . 6 |
+-----------+-----------+-----------+
| . . . | 4 . 7 | . 5 . |
| . 1 . | . . . | . 4 . |
| . . . | . 2 . | 8 . 1 |
+-----------+-----------+-----------+
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play online |
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nataraj
Joined: 03 Aug 2007 Posts: 1048 Location: near Vienna, Austria
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Posted: Fri Nov 21, 2008 4:34 pm Post subject: |
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It starts off with an m-wing:
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+--------------------------+--------------------------+--------------------------+
| 8 57# 6 | 13 9 35* | 2 17# 4 |
| 257 9 1257 | 168 4 -56 | 57* 3 78 |
| 35 4 135 | 7 58 2 | 569 169 89 |
+--------------------------+--------------------------+--------------------------+
| 1 37 379 | 2 6 8 | 4 79 5 |
| 6 2 79 | 5 3 4 | 1 8 79 |
| 4 58 58 | 9 7 1 | 3 2 6 |
+--------------------------+--------------------------+--------------------------+
| 239 368 238 | 4 1 7 | 69 5 23 |
| 23579 1 2357 | 368 58 3569 | 679 4 23 |
| 3579 3567 4 | 36 2 3569 | 8 679 1 |
+--------------------------+--------------------------+--------------------------+
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m-wing (5)r2c7=r1c6 (via SL (7) in row 1), removes 5 from r2c6.
With 6 gone from r2c4, there is now an xy-wing 17-78-18 box 3/row 2 and the puzzle is solved. Very enjoyable. |
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storm_norm
Joined: 18 Oct 2007 Posts: 1741
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Posted: Fri Nov 21, 2008 6:30 pm Post subject: |
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I thought so too. nothing stood out so a careful inspection was needed. |
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cgordon
Joined: 04 May 2007 Posts: 769 Location: ontario, canada
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Posted: Fri Nov 21, 2008 9:29 pm Post subject: Sir cgordon |
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Today is undoubtably my finest hour. Although I haven't yet grasped Nataraj's weak-strong-weak Grouped Multi Coloring concept (explained in today's V. Fiendish post) - I did continue with my brilliant strong link method (BS).
Thus there is a strong link for 5 in R1. The right one uses an ER in Box8 to remove <5> in R8C3. The left one uses a transport in B4 to do the same. And it's exactly the same thing for the strong link <7> in R1 for removing the <7> in R8C3.
This leaves a Type 2 UR and then a Type 4 UR in the same cells (R78C3).
If the Queen does Sudokus and checks out this Forum, I'm a shoe-in for the Honours List. |
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nataraj
Joined: 03 Aug 2007 Posts: 1048 Location: near Vienna, Austria
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Posted: Fri Nov 21, 2008 9:46 pm Post subject: |
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Quote: | I did continue with my brilliant strong link method (BS). |
Oh what a brilliant acronym for your method, Craig.
Definitely needs to be trademarked ASAP.
Seriously, the method is quite good. Seeing how you spot the ERs first, I'd simply call that an ER with transport.
P.S. The confusing thing with ERs is that the same name "empty rectangle" denotes both a pattern within a box (which is simply a grouped strong link, in box 8 ) and a larger pattern where that "hinge" is combined with a strong link to provide the elimination.
What we have here is the same situation as with a "useless xy-wing": there is no cell with "5" that sees both ends of the "large" ER (r1c2, r8c5), but one of the ends of that ER can be transported (to r6c3) and now the "5" in r8c3 is toast. |
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