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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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 Posted: Sat Feb 02, 2008 5:37 pm Post subject: Free Press / LA Times Feb 1, 2008 |
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For the moment, I am stuck:
| Code: | Puzzle: FP020108
+-------+-------+-------+
| 4 . . | . . 8 | 1 . . |
| . . . | . 9 3 | . . 6 |
| . . . | 6 . 4 | . . . |
+-------+-------+-------+
| 8 1 . | . . . | 9 6 7 |
| . . 3 | . . . | 4 . . |
| 7 4 9 | . . . | . 3 5 |
+-------+-------+-------+
| . . . | 5 . 1 | . . . |
| 1 . . | 7 8 . | . . . |
| . . 5 | 4 . . | . . 9 |
+-------+-------+-------+ |
Keith |
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Asellus
Joined: 05 Jun 2007
Posts: 865
Location: Sonoma County, CA, USA
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| Posted: Sat Feb 02, 2008 8:28 pm Post subject: |
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| Something fishy did it for me. |
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Earl
Joined: 30 May 2007
Posts: 677
Location: Victoria, KS
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| Posted: Sat Feb 02, 2008 9:13 pm Post subject: LA Times |
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Keith,
I had to use two xy-chains and coloring.
Those facile with medusa will probably find a neater way.
Earl |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Sat Feb 02, 2008 9:26 pm Post subject: |
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After some coloring and a finned X-wing that each removed one <8>, I am stuck here. I am sure that Medusa will do it, but does anyone have a better idea?
| Code: | +----------------+----------------+----------------+
| 4 5679 67 | 2 57 8 | 1 79 3 |
| 25 2578 78 | 1 9 3 | 57 4 6 |
| 359 3579 1 | 6 57 4 | 578 279 28 |
+----------------+----------------+----------------+
| 8 1 2 | 3 4 5 | 9 6 7 |
| 56 56 3 | 9 2 7 | 4 8 1 |
| 7 4 9 | 8 1 6 | 2 3 5 |
+----------------+----------------+----------------+
| 29 2789 478 | 5 36 1 | 36 27 248 |
| 1 236 46 | 7 8 9 | 36 5 24 |
| 36 78 5 | 4 36 2 | 78 1 9 |
+----------------+----------------+----------------+ |
Keith |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Sat Feb 02, 2008 9:39 pm Post subject: |
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| keith wrote: | | I am sure that Medusa will do it ... |
Famous last words |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Sat Feb 02, 2008 10:18 pm Post subject: |
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I spent almost the whole afternoon on this sucker, as three times i made an error resulting in an invalid solution. I used a Finned X-Wing which I'm not sure had any effect, followed by a Medusa wrap.
(The last grid has my Finned Wing on 7 in rows 29). |
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Johan
Joined: 25 Jun 2007
Posts: 206
Location: Bornem Belgium
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| Posted: Sat Feb 02, 2008 10:52 pm Post subject: |
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| From Keith's grid there is a 4-cell xy-chain that takes out <7> in R1C8 and <7> in R7C3, pincer ends are R1C3 and R7C8 |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Sat Feb 02, 2008 10:55 pm Post subject: |
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| Marty R. wrote: | | (The last grid has my Finned Wing on 7 in rows 29). |
Which takes out <7> in R13C2. I am still stuck.
Keith |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Sat Feb 02, 2008 11:01 pm Post subject: |
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| Johan wrote: | | From Keith's grid there is a 4-cell xy-chain that takes out <7> in R1C8 |
Which solves the puzzle after a couple of pairs and an XY-wing.
Except I personally don't like chains if there is not a pattern that suggests where to start.
Nonetheless, nice job, Johan!
Keith |
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Asellus
Joined: 05 Jun 2007
Posts: 865
Location: Sonoma County, CA, USA
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| Posted: Sat Feb 02, 2008 11:11 pm Post subject: |
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Hmmm...
Seems I made some lucky error earlier, since I only needed the Finned X-Wings. (There are two, one with <7> and one with <8>. By the way, the one for <8> removes both of the <8>s Keith eliminated. The preceding coloring step isn't necessary.)
In repeating the puzzle, I, too, needed the XY Chain and XY Wing.
It's interesting that these newspaper puzzles are requiring such techniques. |
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storm_norm
Joined: 18 Oct 2007
Posts: 1741
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| Posted: Sun Feb 03, 2008 12:37 am Post subject: |
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| Quote: | | It's interesting that these newspaper puzzles are requiring such techniques |
does that mean that the public is asking for this difficulty for a paper puzzle?? |
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storm_norm
Joined: 18 Oct 2007
Posts: 1741
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| Posted: Sun Feb 03, 2008 12:55 am Post subject: |
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| Marty R. wrote: | I spent almost the whole afternoon on this sucker, as three times i made an error resulting in an invalid solution. I used a Finned X-Wing which I'm not sure had any effect, followed by a Medusa wrap.
(The last grid has my Finned Wing on 7 in rows 29). |
Marty,
did your medusa wrap include the {7,8} pair in r9c2?? if so then we did the same thing |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Sun Feb 03, 2008 4:46 am Post subject: |
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| Quote: | | did your medusa wrap include the {7,8} pair in r9c2?? if so then we did the same thing |
Norm,
Sorry, I just can't remember. But I'd be resorting to brute force a lot more had I not learned Medusa. |
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nataraj
Joined: 03 Aug 2007
Posts: 1048
Location: near Vienna, Austria
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| Posted: Sun Feb 03, 2008 1:22 pm Post subject: |
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no-medusa solution:
- use coloring (skyscraper, kite) to remove 8 from r2c7, r3c2
- 2 xy-chains (involving the useless xy-wing 79-27-29) removed 7 from cell(s)
a) r1c8 r7c3: chain '76'(r1c3)via r8c3,r8c9 to '27'(r7c8)
b) r7c3 r1c2 r2c2 r3c2: chain '76'(r1c3) via r8c3,r8c9,r7c8,r9c7 to '87'(r9c2)
in this position
| Code: |
+--------------------------+--------------------------+--------------------------+
| 4 5679 67 | 2 57 8 | 1 79 3 |
| 25 2578 78 | 1 9 3 | 57 4 6 |
| 359 3579 1 | 6 57 4 | 578 279 28 |
+--------------------------+--------------------------+--------------------------+
| 8 1 2 | 3 4 5 | 9 6 7 |
| 56 56 3 | 9 2 7 | 4 8 1 |
| 7 4 9 | 8 1 6 | 2 3 5 |
+--------------------------+--------------------------+--------------------------+
| 29 2789 478 | 5 36 1 | 36 27 248 |
| 1 236 46 | 7 8 9 | 36 5 24 |
| 36 78 5 | 4 36 2 | 78 1 9 |
+--------------------------+--------------------------+--------------------------+ |
Two xy_wings here:
| Code: |
+--------------------------+--------------------------+--------------------------+
| 4 56 67 | 2 57 8 | 1 9 3 |
| 25 28 78 | 1 9 3 | 57 4 6 |
| 39 39 1 | 6 57 4 | 578 27 28 |
+--------------------------+--------------------------+--------------------------+
| 8 1 2 | 3 4 5 | 9 6 7 |
| 56 56 3 | 9 2 7 | 4 8 1 |
| 7 4 9 | 8 1 6 | 2 3 5 |
+--------------------------+--------------------------+--------------------------+
| 29 2789 48 | 5 36 1 | 36 27 248 |
| 1 23 46 | 7 8 9 | 36 5 24 |
| 36 78 5 | 4 36 2 | 78 1 9 |
+--------------------------+--------------------------+--------------------------+
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39-29-23 (pivot r7c1)
29-23-39 (pivot r8c2)
and the rest is singles ... |
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ravel
Joined: 21 Apr 2006
Posts: 536
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| Posted: Sun Feb 03, 2008 3:45 pm Post subject: |
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I wanted to use this nice deadly pattern. A bit complicated, but fun (and finding an xy-chain normally takes me longer).
| Code: | *-----------------------------------------------------------*
| 4 5679 67 | 2 57 8 | 1 79 3 |
| 25 2578 78 | 1 9 3 | 57 4 6 |
|#359 #3579 1 | 6 57 4 | 578 279 28 |
|-------------------+-------------------+-------------------|
| 8 1 2 | 3 4 5 | 9 6 7 |
|#56 #56 3 | 9 2 7 | 4 8 1 |
| 7 4 9 | 8 1 6 | 2 3 5 |
|-------------------+-------------------+-------------------|
| 29 2789 478 | 5 #36 1 |#36 27 248 |
| 1 #236 46 | 7 8 9 |#36 5 24 |
|#36 78 5 | 4 #36 2 | 78 1 9 |
*-----------------------------------------------------------*
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Note that in the UR 57 in r13c25 you can take out 7 in r3c2.
So we have r3c12=9 or r8c2=2.
r3c12=9 => r3c8<>9 => r1c8=9.
r8c2=2 => r7c1=9 => r79c2=78 => r7c3=4 => r8c3=6 => r1c3=7 => r1c8=9
Coloring on 7 and an xy-wing after that. |
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