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daj95376
Joined: 23 Aug 2008
Posts: 3854
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 Posted: Thu Jan 29, 2009 6:52 pm Post subject: Set NNP Puzzle 72 -- Advanced |
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Dang  This puzzle is trivial until it comes to a stop with only a few cells to resolve.
| Code: | +-----------------------+
| . . . | . 2 9 | . . . |
| . 6 . | . . 7 | . 1 . |
| . . . | 5 . . | . 7 . |
|-------+-------+-------|
| . . 9 | . 6 . | . 2 . |
| 1 . . | 9 . 8 | . 3 . |
| 6 3 . | . 5 . | . 8 1 |
|-------+-------+-------|
| . . . | . . . | . 6 . |
| . 1 3 | 2 7 6 | 5 9 . |
| . . . | . . 1 | . . 7 |
+-----------------------+
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Play this puzzle online at the Daily Sudoku site
===== ===== ===== ===== ===== ===== ===== ===== ===== Ratings
Can be solved using steps from ...
Basics: Naked/Hidden Single, Naked Pair/Triple, Locked Candidate 1/2
Basics+: Naked Quad, Hidden Pair/Triple/Quad
VH: BUG+1, UR Type 1, X-Wing, XY-Wing, XYZ-Wing
VH+: 2-String Kite, Empty Rectangle, Remote Pair, Skyscraper, Colors, UR Type 2
Advanced: finned/Sashimi X-Wing, Multiple Colors, Swordfish, M-Wing, W-Wing, XY-Chain
Extreme: Jellyfish, (but mostly) Chain |
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cgordon
Joined: 04 May 2007
Posts: 769
Location: ontario, canada
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| Posted: Thu Jan 29, 2009 7:26 pm Post subject: |
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I'm not sure about including the VH steps: eg:
VH: BUG+1, UR Type 1, X-Wing, XY-Wing, XYZ-Wing
VH+: 2-String Kite, Empty Rectangle, Remote Pair, Skyscraper, Colors, UR Type 2
After basics none of them seem to apply (unless I'm missing something obvious).
This is one of those I alluded to in the earlier post today for N60. Easy start - impossible finish. You should preserve both as definitive cases. |
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wapati
Joined: 10 Jun 2008
Posts: 472
Location: Brampton, Ontario, Canada.
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| Posted: Thu Jan 29, 2009 8:57 pm Post subject: |
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This needs a 4 cell xy-chain, or an ALS that is identical in cells and eliminations. I like it.  |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Thu Jan 29, 2009 11:10 pm Post subject: |
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| cgordon wrote: | I'm not sure about including the VH steps: eg:
VH: BUG+1, UR Type 1, X-Wing, XY-Wing, XYZ-Wing
VH+: 2-String Kite, Empty Rectangle, Remote Pair, Skyscraper, Colors, UR Type 2
After basics none of them seem to apply (unless I'm missing something obvious).
This is one of those I alluded to in the earlier post today for N60. Easy start - impossible finish. You should preserve both as definitive cases. |
Craig: I'm not sure if I understand your point. Since I only colored Basics and Advanced steps used by my solver, the techniques in the other ratings weren't present.
wapati: The XY-Chain is all that I found as well. I posted this puzzle mostly out of curiousity to see if anything other than an ALS or chain was present. |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Fri Jan 30, 2009 12:37 am Post subject: |
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I am still looking for the 4-cell chain, but I did find a 5-cell chain that deleted <5> from r5c3. However I still needed a xy-wing <289> and a BUG+1 to complete the puzzle.
Ted |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Fri Jan 30, 2009 1:20 am Post subject: |
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| tlanglet wrote: | I am still looking for the 4-cell chain, but I did find a 5-cell chain that deleted <5> from r5c3. However I still needed a xy-wing <289> and a BUG+1 to complete the puzzle.
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Congratulations on finding a solution. This puzzle is a stinker! Here's wapati's XY-Chain. No XY/XYZ-Wings or other 4-cell XY-Chains present -- ironic given all of the bivalue cells present.
| Code: | +-----------------------------------------------------+
| 7 4 1 | 6 2 9 | 8 5 3 |
| 25-9 6 25 | 3 8 7 | 24 1 a49 |
| 3 289 28 | 5 1 4 | 26 7 69 |
|-----------------+-----------------+-----------------|
| c58 578 9 | 1 6 3 | 47 2 b45 |
| 1 257 257 | 9 4 8 | 67 3 56 |
| 6 3 4 | 7 5 2 | 9 8 1 |
|-----------------+-----------------+-----------------|
| d89 789 78 | 4 3 5 | 1 6 2 |
| 4 1 3 | 2 7 6 | 5 9 8 |
| 25 25 6 | 8 9 1 | 3 4 7 |
+-----------------------------------------------------+
# 27 eliminations remain
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Fri Jan 30, 2009 2:09 am Post subject: |
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After basics: | Code: | +-------------+-------------+-------------+
| 7 4 1 | 6 2 9 | 8 5 3 |
| 259 6 25 | 3 8 7 | 24 1 49 |
| 3 289 28c | 5 1 4 | 26b 7 69 |
+-------------+-------------+-------------+
| 58 578 9 | 1 6 3 | 47 2 45 |
| 1 257 257 | 9 4 8 | 67a 3 56 |
| 6 3 4 | 7 5 2 | 9 8 1 |
+-------------+-------------+-------------+
| 89 789 78d | 4 3 5 | 1 6 2 |
| 4 1 3 | 2 7 6 | 5 9 8 |
| 25 25 6 | 8 9 1 | 3 4 7 |
+-------------+-------------+-------------+ |
There is another 4-cell chain abcd that takes out <7> in R5C3.
Keith |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Fri Jan 30, 2009 4:31 am Post subject: |
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| keith wrote: | | There is another 4-cell chain abcd that takes out <7> in R5C3. |
Oops!!! 
I only kept the 4-cell XY-Chain in my records that cracked the puzzle. Thanks keith for correcting my oversight! |
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wapati
Joined: 10 Jun 2008
Posts: 472
Location: Brampton, Ontario, Canada.
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| Posted: Fri Jan 30, 2009 4:43 am Post subject: |
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I found a 5 cell xy-chain but it doesn't do enough. Still would need an xy-wing and BUG, for instance.
| Code: | .---------------.---------.-----------.
| 7 4 1 | 6 2 9 | 8 5 3 |
| 259 6 #25 | 3 8 7 |#24 1 #49 |
| 3 289 28 | 5 1 4 | 26 7 #69 |
:---------------+---------+-----------:
| 58 578 9 | 1 6 3 | 47 2 45 |
| 1 257 27-5| 9 4 8 | 67 3 #56 |
| 6 3 4 | 7 5 2 | 9 8 1 |
:---------------+---------+-----------:
| 89 789 78 | 4 3 5 | 1 6 2 |
| 4 1 3 | 2 7 6 | 5 9 8 |
| 25 25 6 | 8 9 1 | 3 4 7 |
'---------------'---------'-----------' |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Fri Jan 30, 2009 4:51 am Post subject: |
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| daj95376 wrote: | | keith wrote: | | There is another 4-cell chain abcd that takes out <7> in R5C3. |
Oops!!!
I only kept the 4-cell XY-Chain in my records that cracked the puzzle. Thanks keith for correcting my oversight! |
I was not intending to "correct" anything! This chain (if you continue to disregard the one that cracks the puzzle) leads to an interesting path of a couple more 4-cell chains, or one more 4-cell chain and a BUG+1.
It's the journey, not the destination!
Keith |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Tue Feb 03, 2009 5:40 am Post subject: |
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| I saw nothing so I went straight to Medusa. That solved it so quickly that I just knew I missed something else. It seems that a lot of Medusa-solved puzzles also have chains. |
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