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daj95376
Joined: 23 Aug 2008
Posts: 3854
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 Posted: Wed Jun 02, 2010 4:33 pm Post subject: Puzzle 10/06/02: (B) |
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Not many VH+ steps, but that's no help.
| Code: | +-----------------------+
| 3 . 9 | . 7 1 | 5 . . |
| . . . | . . 5 | . . . |
| . . 8 | . . . | . 3 . |
|-------+-------+-------|
| . . 5 | 4 . . | . . . |
| 9 . . | . 6 . | . . . |
| 8 6 . | . . 9 | 4 . 7 |
|-------+-------+-------|
| 1 . . | . . 6 | 9 7 . |
| . . 4 | . . . | 3 . . |
| 7 . . | . . . | . . 6 |
+-----------------------+
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Play this puzzle online at the Daily Sudoku site |
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peterj
Joined: 26 Mar 2010
Posts: 974
Location: London, UK
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| Posted: Thu Jun 03, 2010 7:37 am Post subject: |
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Indeed, nice to xx out of bivalue mode for a bit!
| Quote: | grouped kite(2) (2)r6c8=r6c45-r5c6=r8c6; r8c8<>2
skyscraper(8) (8)r5c6=r8c6-r8c8=r9c7; r5c7<>8
xy-wing(1-28) r5c6; r5c4<>1, r4c789<>1 |
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Mogulmeister
Joined: 03 May 2007
Posts: 1151
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| Posted: Thu Jun 03, 2010 9:18 am Post subject: |
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Very similar although I'm not sure the skyscraper isn't called a 2 string kite!
| Quote: | ER removes 2 from r8c8
Two String Kite/Baphomet removes 8 from r5c7
XY Wing <128> removes 1s from r6c789 and r5c4 |
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peterj
Joined: 26 Mar 2010
Posts: 974
Location: London, UK
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| Posted: Thu Jun 03, 2010 10:19 am Post subject: |
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| fwiw I call them "kites" if the two strong links see each other in the same block and "skyscrapers" if they see each other across a row or column - agree it doesnt have a skyscraper shape though! |
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ronk
Joined: 07 May 2006
Posts: 398
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| Posted: Thu Jun 03, 2010 12:18 pm Post subject: |
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| peterj wrote: | | fwiw I call them "kites" if the two strong links see each other in the same block and "skyscrapers" if they see each other across a row or column - agree it doesnt have a skyscraper shape though! |
Based on your AIC, shape is an Empty Rectangle pattern. |
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Mogulmeister
Joined: 03 May 2007
Posts: 1151
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| Posted: Thu Jun 03, 2010 2:00 pm Post subject: |
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I'm sounding a bit antiquated today but I guess my lexicon goes back to Havard days where I first encountered the phrases "2 string kite" and "skyscraper" which were fairish attempts at describing the physical shape of these things. The skyscraper usually had two parallel strong links of differing length whose "bases" were in the same band/house/stack.
I'm reminded of my chemistry days when we had to describe elements and compounds by their shapes and properties.
Thanks Peter and Ronk. |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Thu Jun 03, 2010 3:20 pm Post subject: |
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| ronk wrote: | | peterj wrote: | | fwiw I call them "kites" if the two strong links see each other in the same block and "skyscrapers" if they see each other across a row or column - agree it doesnt have a skyscraper shape though! |
Based on your AIC, shape is an Empty Rectangle pattern. |
For What Little It Is Worth:
If the strong link in the box is ungrouped, i.e. 2 cells, then I go back to Nick70's thread and call it a turbot fish.
If the strong link in the box is grouped, i.e. 3/4/5 cells, then I call it an Empty Rectangle.
| ronk's Empty Rectangle link wrote: | This technique is a special case of Grouped Turbot Fish.
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peterj's box is ungrouped.
===== ===== ===== ===== =====
I'm impressed that both the Empty Rectangle and grouped (2-String) Kite were found for r8c8<>2. |
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peterj
Joined: 26 Mar 2010
Posts: 974
Location: London, UK
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| Posted: Thu Jun 03, 2010 3:48 pm Post subject: |
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| Thanks - I can see that skyscraper is definitely the wrong name. I'll go with turbot fish I think for this common pattern then from now on - I also tend to think of ERs as having groups in a box. |
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ronk
Joined: 07 May 2006
Posts: 398
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| Posted: Thu Jun 03, 2010 6:47 pm Post subject: |
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| daj95376 wrote: | For What Little It Is Worth:
If the strong link in the box is ungrouped, i.e. 2 cells, then I go back to Nick70's thread and call it a turbot fish.
If the strong link in the box is grouped, i.e. 3/4/5 cells, then I call it an Empty Rectangle.
| ronk's Empty Rectangle link wrote: | This technique is a special case of Grouped Turbot Fish.
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The skyscraper, kite and empty rectangle techniques are all examples of turbot fish. Candidate grouping should not be, and for the most part is not, intrinsically part of their definitions. |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Thu Jun 03, 2010 9:38 pm Post subject: |
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| ronk wrote: | | The skyscraper, kite and empty rectangle techniques are all examples of turbot fish. Candidate grouping should not be, and for the most part is not, intrinsically part of their definitions. |
I agree with you. However, I had a previous discussion (in this forum) on this topic and the agreement wasn't as mutual. Since then, I try to limit the basic turbot fish term to mean the ungrouped 5-vertice/5-edge polygon description presented by Nick70 ... and use Skyscraper, Kite, and Empty Rectangle techniques as grouped/ungrouped derivations from Nick70's thread. Since peterj's pattern matches Nick70's description, I refer to it as a turbot fish.
The biggest exception is my use of the turbot subset of VH+ in my ratings.
| Code: | ===== ===== ===== Ratings are Accumulative in 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
turbot: 2-String Kite, Skyscraper, Empty Rectangle, finned/Sashimi X-Wing
VH+: Remote Pair, XYZ-Wing, UR Type 2/4
XY: gM-Wing, W-Wing, XY-Chain, BUG+2, BUG+3, other URs
Extreme: Chain, Loop, SIN (Single Inference Network)
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Mogulmeister
Joined: 03 May 2007
Posts: 1151
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| Posted: Thu Jun 03, 2010 9:47 pm Post subject: |
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| I think it is OK to use the turbot fish subset descriptions - it is especially useful to folks learning the game. |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Thu Jun 03, 2010 9:54 pm Post subject: |
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My three step solution.............
ANP(18=2)r8c8,r9c7 - r8c6 = r5c6 - r5c78 = (2)r6c8; r8c8<>2
w-wing 18 r4c5 & r9c7 SL 1 r59c4; r4c7,r9c5<>8 plus transport: (8 )r4c5 - r2c5 = (8 )*r12c4 - r7c4 = (8)r7c2; *r9c4, r9c2<>8
xy-wing -128 with vertex 28 r5c6; r4c79,r5c4<>1
Ted |
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Mogulmeister
Joined: 03 May 2007
Posts: 1151
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| Posted: Thu Jun 03, 2010 9:58 pm Post subject: |
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| What are the *'s indicating Ted ? |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Thu Jun 03, 2010 10:09 pm Post subject: |
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| tlanglet wrote: | My three step solution.............
ANP(18=2)r8c8,r9c7 - r8c6 = r5c6 - r5c78 = (2)r6c8; r8c8<>2
w-wing 18 r4c5 & r9c7 SL 1 r59c4; r4c7,r9c5<>8 plus transport: (8 )r4c5 - r2c5 = (8 )*r12c4 - r7c4 = (8)r7c2; *r9c4, r9c2<>8
xy-wing -128 with vertex 28 r5c6; r4c79,r5c4<>1
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Ted, the part in red is extraneous. You have an Empty Rectangle in <2>.
BTW:
Are we all in agreement that ANP(18=2)r8c8,r9c7 is a shortened notation for np(18)r8c8,r9c7 = (2)r8c8 ?
| Code: | +-----------------------------------------------------------------------+
| 3 2 9 | 68 7 1 | 5 468 48 |
| 4 17 6 | 2389 2389 5 | 1278 1289 1289 |
| 5 17 8 | 269 29 4 | 1267 3 129 |
|-----------------------+-----------------------+-----------------------|
| 2 3 5 | 4 18 7 | 168 1689 189 |
| 9 4 7 | 1258 6 28 | 128 1258 3 |
| 8 6 1 | 235 235 9 | 4 25 7 |
|-----------------------+-----------------------+-----------------------|
| 1 58 3 | 258 2458 6 | 9 7 2458 |
| 6 589 4 | 7 12589 28 | 3 128 1258 |
| 7 589 2 | 1589 14589 3 | 18 148 6 |
+-----------------------------------------------------------------------+
# 84 eliminations remain
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Mogulmeister
Joined: 03 May 2007
Posts: 1151
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| Posted: Thu Jun 03, 2010 10:35 pm Post subject: |
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| Daj wrote: | | Are we all in agreement that ANP(18=2)r8c8,r9c7 is a shortened notation for np(18)r8c8,r9c7 = (2)r8c8 ? |
Looks good to me Danny - imho the ANP is a condensed form that I admit to preferring as I like the flow of the ANP narrative which is quite explicit. |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Thu Jun 03, 2010 10:50 pm Post subject: |
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| tlanglet wrote: | w-wing 18 r4c5 & r9c7 SL 1 r59c4; r4c7,r9c5<>8 plus transport: (8 )r4c5 - r2c5 = (8 )*r12c4 - r7c4 = (8 )r7c2; *r9c4, r9c2<>8
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| Code: | +-----------------------------------------------------------------------+
| 3 2 9 | 68 7 1 | 5 68 4 |
| 4 17 6 | 2389 2389 5 | 1278 1289 189 |
| 5 17 8 | 269 29 4 | 1267 3 19 |
|-----------------------+-----------------------+-----------------------|
| 2 3 5 | 4 18 7 | 168 1689 189 |
| 9 4 7 | 1258 6 28 | 128 1258 3 |
| 8 6 1 | 235 235 9 | 4 25 7 |
|-----------------------+-----------------------+-----------------------|
| 1 58 3 | 258 4 6 | 9 7 25 |
| 6 589 4 | 7 12589 28 | 3 18 25 |
| 7 589 2 | 1589 1589 3 | 18 4 6 |
+-----------------------------------------------------------------------+
# 69 eliminations remain
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Ted ... Ted ... Ted: You sure do know how to make things interesting. I assume that you mean ...
(8=1)r9c7 - r9c4 = r5c4 - (1=8 )*r4c6 - r2c5 = (8 )**r12c4 - r7c4 = (8 )***r7c2
(*) W-Wing portion of chain => r4c7,r9c5<>8
(**) Next extension of chain => r9c4<>8
(***) Final extension of chain => r9c2<>8 |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Fri Jun 04, 2010 1:27 am Post subject: |
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| Mogulmeister wrote: | | What are the *'s indicating Ted ? |
Danny already posted the idea above to denote deletions along the path of a chain. I saw this technique on the Eureka forum. Did I misunderstand the Eureka usage or is some other notation preferred?
Ted |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Fri Jun 04, 2010 1:58 am Post subject: |
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Danny,
Yes, you are 100% correct about my intentions on using * to indicate a deletion along a path. I saw this technique on Eureka in a manner identical to the configuration I found in this puzzle. However, I think your multi-level use of * is better and I will use it at the next opportunity.
As for acceptance of the ANP(xy=z) notation, I have no idea if others accept it as the standard. I do think the intent is obvious.
Also. while reviewing AN[PTQ], where do you place them in your scale of difficulty? I believe they are in the VH+ class since they have a pattern and basically involve extending/transporting type of operations.
Ted
Last edited by tlanglet on Fri Jun 04, 2010 3:07 am; edited 1 time in total |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Fri Jun 04, 2010 2:04 am Post subject: |
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| tlanglet wrote: | Did I misunderstand the Eureka usage or is some other notation preferred?
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I haven't been to the Eureka! forum in some time ... and didn't follow most of what they were doing then. It appeared that they were trying to find the most convoluted solutions possible so they could gain the most points.
In any event, I doubt if they would have presented your step the same way you did. I have no idea if there is a "best" way to present it, but I would have probably chosen:
| Code: | | ************ W-Wing ************ |
(8=1)r9c7 - r9c4 = r5c4 - (1=8 )r4c6 - r2c5 = (8 )r12c4 - r7c4 = (8 )r7c2
\ \ \
\ \ r9c2<>8
\ r9c4<>8
r4c7,r9c5<>8
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Mogulmeister
Joined: 03 May 2007
Posts: 1151
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| Posted: Fri Jun 04, 2010 6:07 am Post subject: |
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| tlanglet wrote: | | Mogulmeister wrote: | | What are the *'s indicating Ted ? |
Danny already posted the idea above to denote deletions along the path of a chain. I saw this technique on the Eureka forum. Did I misunderstand the Eureka usage or is some other notation preferred?
Ted |
No - I followed you the first time and had no difficulty - it was clear to me but because I was looking purely at the links/eliminations I didn't think about the classification of the sub-components. Nice journey Ted and great explanations from both you and Danny! |
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