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wapati
Joined: 10 Jun 2008 Posts: 472 Location: Brampton, Ontario, Canada.
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Posted: Mon Jul 14, 2008 7:25 am Post subject: Can you find an M-wing? |
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This puzzle is a hoot. (Jsudoku generated.)
It starts of nicely and then nearly every step is advanced.
Expect to see: 2-string kites, finned and plain x-wings, ERs, finned sword, UR4, xy-wing and W-wings, unless you find the M-wing. Oh, if you miss the M-wing add xyz and sashimi sword, at least.
It is possible to ruin the M-wing without using a W-wing. An extra W-wing saves the day. Good hunting!
Code: | 1 . .|3 2 .|. . .
3 . 8|. . .|1 . .
7 . .|. . .|9 5 .
-----+-----+-----
. 1 .|. 8 5|. . .
. . .|1 . 2|. . 5
4 8 .|. 3 .|. . 2
-----+-----+-----
. 2 .|. . .|. 8 .
. . 6|2 . 3|. . .
. . .|8 . .|2 9 6 |
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storm_norm
Joined: 18 Oct 2007 Posts: 1741
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Posted: Mon Jul 14, 2008 8:42 am Post subject: |
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my shortest path,
coloring 4
UR
xy-wing
Code: | .---------------------.---------------------.---------------------.
| 1 5 49 | 3 2 479 | 467 467 8 |
| 3 469 8 | 45679 56 4679 | 1 2 47 |
| 7 46 2 | 46 1 8 | 9 5 3 |
:---------------------+---------------------+---------------------:
| 2 1 37 | 467 8 5 | 467 3467 9 |
| 6 379 379 | 1 47 2 | 8 347 5 |
| 4 8 5 | 679 3 679 | 67 1 2 |
:---------------------+---------------------+---------------------:
| 9 2 147 | 4567 56 1467 | 3 8 47 |
| 8 47 6 | 2 9 3 | 5 47 1 |
| 5 347 1347 | 8 47 147 | 2 9 6 |
'---------------------'---------------------'---------------------' |
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Earl
Joined: 30 May 2007 Posts: 677 Location: Victoria, KS
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Posted: Mon Jul 14, 2008 2:08 pm Post subject: M wing |
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Coloring on 4, then the brute force of an xy-chain does it.
Earl |
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nataraj
Joined: 03 Aug 2007 Posts: 1048 Location: near Vienna, Austria
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Posted: Tue Jul 15, 2008 6:40 am Post subject: |
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I did find an m-wing right after basics, but it did not solve the puzzle. So I went the coloring way (on 4)
Code: |
+--------------------------+--------------------------+--------------------------+
| 1 5 49 | 3 2 479 | 467 467 8 |
| 3 469 8 | 45679 56 4679 | 1 2 47 |
| 7 46 2 | 46 1 8 | 9 5 3 |
+--------------------------+--------------------------+--------------------------+
| 2 1 37 | 467 8 5 | 467 3467 9 |
| 6 379 379 | 1 47 2 | 8 347 5 |
| 4 8 5 | 679 3 679 | 67 1 2 |
+--------------------------+--------------------------+--------------------------+
| 9 2 147 | 4567 56 1467 | 3 8 47 |
| 8 47 6 | 2 9 3 | 5 47 1 |
| 5 347 1347 | 8 47 147 | 2 9 6 |
+--------------------------+--------------------------+--------------------------+
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4 can be removed from r2c2 (same as the m-wing), r2c4, r2c6, and (!) from r4c4 by a very long chain:
4:-r4c7=r1c7-r2c9=r7c9-r8c8=r8c2-r3c2=r3c4-;r4c4<>4
Code: |
+·····+·····+·····+
· 9· o·* o ·
· · ·| ·
· o ·o o·| 7·
· · ·| |·
· 6---6 ·| |·
+·····+·····+|···|+
· ·* ·* o |·
· · \ · |·
· · 7-----* |·
· · | · |·
· · | · |·
+·····+··|··+····|+
· o·o | o· 7·
· · | · / ·
· 7-----------7 ·
· · | · ·
· o o· 7 o· ·
+·····+·····+·····+
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After cleanup and (once more) coloring on 4 (simple skyscraper cols 2 and 4 this time), this is where a w-wing becomes very useful (again no m-wing):
Code: |
+--------------------------+--------------------------+--------------------------+
| 1 5 49 | 3 2 -49 | 67 67 8 |
| 3 69 8 | 5679 56# 679 | 1 2 4 |
| 7 46 2 | 46* 1 8 | 9 5 3 |
+--------------------------+--------------------------+--------------------------+
| 2 1 37 | 67 8 5 | 4 367 9 |
| 6 39 379 | 1 4 2 | 8 37 5 |
| 4 8 5 | 679 3 679 | 67 1 2 |
+--------------------------+--------------------------+--------------------------+
| 9 2 1 |-456 56# 46* | 3 8 7 |
| 8 7 6 | 2 9 3 | 5 4 1 |
| 5 34 34 | 8 7 1 | 2 9 6 |
+--------------------------+--------------------------+--------------------------+
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Where IS that elusive m-wing? |
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wapati
Joined: 10 Jun 2008 Posts: 472 Location: Brampton, Ontario, Canada.
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Posted: Tue Jul 15, 2008 10:36 am Post subject: |
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nataraj wrote: |
Where IS that elusive m-wing? |
"#" marks the strong links on 7 for the basic pattern.
"@" marks the strong links on 4 for the pointing arm.
"*" marks the target and 4 is eliminated.
Code: | +-------------------+-------------------+-------------------+
| 1 5 49 | 3 2 79 | 467 67 8 |
| 3 69 8 | 47@ 5 69 | 1 2 47@ |
| 7 *6-4 2 | 46@ 1 8 | 9 5 3 |
+-------------------+-------------------+-------------------+
| 2 1 37 | 67 8 5 | 467 3467 9 |
| 6 379 379 | 1 4 2 | 8 37 5 |
| 4 8 5 | 9 3 67 | 67 1 2 |
+-------------------+-------------------+-------------------+
| 9 2 #17 | 5 6 14 | 3 8 #47@ |
| 8 #47 6 | 2 9 3 | 5 47 1 |
| 5 34 134 | 8 7 14 | 2 9 6 |
+-------------------+-------------------+-------------------+
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ravel
Joined: 21 Apr 2006 Posts: 536
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Posted: Tue Jul 15, 2008 1:00 pm Post subject: |
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Code: | .---------------------.---------------------.---------------------.
| 1 5 *49 | 3 2 479 |*467 *467 8 |
| 3 69 8 | 4579 56 4679 | 1 2 @47 |
| 7 @46 2 | 46 1 8 | 9 5 3 |
:---------------------+---------------------+---------------------:
| 2 1 37 | 467 8 5 | 467 3467 9 |
| 6 379 379 | 1 47 2 | 8 347 5 |
| 4 8 5 | 679 3 679 | 67 1 2 |
:---------------------+---------------------+---------------------:
| 9 2 14-7 | 457 56 1467 | 3 8 #47 |
| 8 #47 6 | 2 9 3 | 5 4-7 1 |
| 5 347 1347 | 8 47 147 | 2 9 6 |
'---------------------'---------------------'---------------------'
| Nice puzzle.
After the remote naked pair 47 to eliminate 4 from r2c2 and the UR 56 (r27c4<>6) there is a w-wing 47 connected by a grouped kite in 4, which takes out 7 from r7c3 and r8c8. An xy-wing then solves it.
Did not see the M-wing either - needs the elimination of 4 in r1c6 (??). Suppose, this would be called remote naked pair (or kite or - using r7c3 - an M-wing) with pincer coloring or transport here.
[Added:]btw, I liked todays wapati on the programmers forum very much, i had 4 types of UR, a kite, a w-wing connected with a grouped link and an xy-wing. |
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nataraj
Joined: 03 Aug 2007 Posts: 1048 Location: near Vienna, Austria
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Posted: Thu Jul 17, 2008 9:43 pm Post subject: |
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Thanks, wapati, for pointing out the m-wing. I did not look further than to look for a simple strong link (for the pointing arm), but of course any (even multi-) coloring chain will do...
nice! |
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