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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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 Posted: Sat Jul 03, 2010 1:13 pm Post subject: Free Press Jul 2, 2010 |
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Not yet started:
| Code: |
Puzzle: FP070210
+-------+-------+-------+
| . . . | . . . | 3 2 . |
| 1 . . | . . 7 | . . 6 |
| . 2 . | . 5 . | 7 1 . |
+-------+-------+-------+
| . 8 . | . . 2 | . . . |
| . . 9 | . 6 . | 5 . . |
| . 6 . | 7 . . | . . . |
+-------+-------+-------+
| . 9 . | . 2 . | . 4 . |
| 5 . . | 1 . . | . . . |
| . 7 8 | . . . | . . . |
+-------+-------+-------+
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Play this puzzle online at the Daily Sudoku site
Keith |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Sat Jul 03, 2010 5:04 pm Post subject: |
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This looks totally unreasonable to me. Don't waste your time.
Keith |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Sat Jul 03, 2010 6:25 pm Post subject: |
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| I agree. After one elimination from a Hidden UR I hit the brick wall. |
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Mogulmeister
Joined: 03 May 2007
Posts: 1151
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| Posted: Sat Jul 03, 2010 8:00 pm Post subject: |
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It is a totally horrid puzzle Keith, so few bivalves after basics and your warning is very well made. After basics (hyuk!)
| Code: | +----------------------+----------------------+----------------------+
| 89 45 7 | 4689 1489 14689 | 3 2 4589 |
| 1 345 34 | 2 489 7 | 489 589 6 |
| 89 2 6 | 3489 5 3489 | 7 1 489 |
+----------------------+----------------------+----------------------+
| 347 8 345 | 3459 1349 2 | 1469 3679 1349 |
| 2347 1 9 | 348 6 348 | 5 378 2348 |
| 234 6 2345 | 7 13489 134589 | 1489 389 123489 |
+----------------------+----------------------+----------------------+
| 36 9 1 | 3568 2 3568 | 68 4 7 |
| 5 34 234 | 1 7 34689 | 2689 3689 389 |
| 2346 7 8 | 3469 349 3469 | 1269 3569 1359 |
+----------------------+----------------------+----------------------+
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However, there is a rather grungy way round making use of strong links on 1,2 & 5 and I apologise in advance.
IF ANP(5=34)r2c23-(4=89)r2c57-(89=5)r2c8-r9c8=(5-1)r9c9=(1-2)r9c7=(2)r8c7 so r8c7=2
Then reverse same ANP
If ANP(34=5)r2c23-(5=4)r1c2-(4=3)r8c2-(3=689)r7c7|r8c89-(689=2)r8c7
In both cases r8c7=2 and puzzle is solved.........I've had a few Saturday libations so tongue is firmly in cheek......
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peterj
Joined: 26 Mar 2010
Posts: 974
Location: London, UK
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| Posted: Sat Jul 03, 2010 8:51 pm Post subject: |
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A magnificent edifice! 
Though of course considering the potential UR(34) makes it much simpler 
UR(34) r28c23; r2c2=5 || r8c3=2
but (5)r2c2=r2c8 - r9c8=(5-1)r9c9=(1-2)r9c7=r8c7 - (2)r8c3
=> DP
=> r2c2=5
Singles..
Hindsight is a wonderful thing! Cheers! |
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Mogulmeister
Joined: 03 May 2007
Posts: 1151
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| Posted: Sat Jul 03, 2010 10:48 pm Post subject: |
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So interestingly, the (34=5) in my ANP is also the basis for part of an AUR (Almost Unique Rectangle) and a section of one of the chains figures to break up the Deadly pattern. Nice one Peter.
For the non-notational among you a quick recapitulation: Peter's AUR is saying that to avoid the Deadly pattern (DP), as a minimum, either 5 must be in r2c2 OR 2 must be in r8c3 to break up the DP.
| Code: | +----------------------+----------------------+----------------------+
| 89 45 7 | 4689 1489 14689 | 3 2 4589 |
| 1 34+5 34 | 2 489 7 | 489 589 6 |
| 89 2 6 | 3489 5 3489 | 7 1 489 |
+----------------------+----------------------+----------------------+
| 347 8 345 | 3459 1349 2 | 1469 3679 1349 |
| 2347 1 9 | 348 6 348 | 5 378 2348 |
| 234 6 2345 | 7 13489 134589 | 1489 389 123489 |
+----------------------+----------------------+----------------------+
| 36 9 1 | 3568 2 3568 | 68 4 7 |
| 5 34 34+2 | 1 7 34689 | 2689 3689 389 |
| 2346 7 8 | 3469 349 3469 | 1269 3569 1359 |
+----------------------+----------------------+----------------------+
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So if you take out the proposed 5 in r2c2 (just to leave in the 2 in r8c3 as your only DP breaker) the chain suggests that no 5 also means no 2 in r8c3 and we have the DP. The only option left is to put back the 5 in r2c2. |
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Mogulmeister
Joined: 03 May 2007
Posts: 1151
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| Posted: Sat Jul 03, 2010 11:20 pm Post subject: |
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This puzzle also has a discontinuous loop that bites part of its own tail.
If we take out the 2 in r8c7 then we begin by creating a quad elimination leaving 5 in r9c8.
(2=3689)r8c789|r7c7-(369=5)r9c8-r2c8=r1c9-(5=4)r1c2-(4=3)r8c2-(3=689)r7c7|r8c89-(689=2)r8c7
Removing 2 from r8c7 causes the loop to place a 2 in r8c7. So r8c7 is 2 and puzzle solved........ 
High marks for awkwardness and fun.
Last edited by Mogulmeister on Sat Jul 03, 2010 11:24 pm; edited 1 time in total |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Sat Jul 03, 2010 11:23 pm Post subject: |
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[Prepared w/o knowing of MM's previous message.]
I think Mogulmeister is missing some steps because I can't get basics to account for eliminations r89c9<>2.
I can get a Kite to account for r8c9<>2.
Alternately:
| Code: | after basics
+--------------------------------------------------------------------------------+
| 89 45 7 | 4689 1489 14689 | 3 2 4589 |
| 1 *34+5 *34 | 2 489 7 | 489 589 6 |
| 89 2 6 | 3489 5 3489 | 7 1 489 |
|--------------------------+--------------------------+--------------------------|
| 347 8 345 | 3459 1349 2 | 1469 3679 1349 |
| 2347 1 9 | 348 6 348 | 5 378 2348 |
| 234 6 2345 | 7 13489 134589 | 12489 389 123489 |
|--------------------------+--------------------------+--------------------------|
| 36 9 1 | 3568 2 3568 | 68@ 4 7 |
| 5 *34 *34+2 | 1 7 34689 | 2+689@ 3689@ 2+389@ |
| 2346 7 8 | 3469 349 3469 | 1269 5+369@ 12359 |
+--------------------------------------------------------------------------------+
# 134 eliminations remain
<34> UR r28c23 => r2c2=5 and/or r8c3=2
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However, if r2c2<>5 then r8c3<>2 ...
| Code: | <2,3,5,6,8,9>
(5)r2c2 = r2c8 - (5=2)r78c7,r89c8,r8c9 - (2)r8c3
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... resulting in r2c2=5. |
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Luke451
Joined: 20 Apr 2008
Posts: 310
Location: Southern Northern California
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| Posted: Sat Jul 03, 2010 11:46 pm Post subject: |
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| keith wrote: | This looks totally unreasonable to me. Don't waste your time.
Keith |
That's throwing down the gauntlet, so I had to take the clipboard out to the pool. It was difficult to concentrate while looking over my sunglasses at all those bikinis.
When I came in to post, I was surprized to find you guys had beaten me to the punch with my own stick.
I also used the AUR, but keyed on the ALS (2=3689) in box 9.
Starting fr the SSTS position and considering AUR34r28c23:
(3689=2)als:r8c789,r7c7-(2)r8c3=(5)r2c2-r2c8=(5)r9c8 =>r9c8<>369=5
Sorry for the short-cuts...time's a wastin'! |
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peterj
Joined: 26 Mar 2010
Posts: 974
Location: London, UK
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| Posted: Sun Jul 04, 2010 7:27 am Post subject: |
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| daj95376 wrote: | | I think Mogulmeister is missing some steps because I can't get basics to account for eliminations r89c9<>2. |
Me neither, I must have just copy/pasted his post-basics and worked from that.
However if you walk through the strong link chain using 5,1 and 2 the 2s in r9c7 and r9c9 get eliminated by the placing of, first, a 5 in r9c9 and then a 1 in r9c7. This leaves the only 2s in r8c79 which is still sufficient for the loop.
I guess the ALS is cleaner.
Is there a notation which allows one to express 'placed' values in a chain? |
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Mogulmeister
Joined: 03 May 2007
Posts: 1151
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| Posted: Sun Jul 04, 2010 10:20 am Post subject: |
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| peterj wrote: |
However if you walk through the strong link chain using 5,1 and 2 the 2s in r9c7 and r9c9 get eliminated by the placing of, first, a 5 in r9c9 and then a 1 in r9c7. This leaves the only 2s in r8c79 which is still sufficient for the loop.
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r9c8=(5-1)r9c9=(1-2)r9c7
Obviously got way too implicit - Apologies to all! |
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Luke451
Joined: 20 Apr 2008
Posts: 310
Location: Southern Northern California
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| Posted: Sun Jul 04, 2010 2:02 pm Post subject: |
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| Peter wrote: | | Is there a notation which allows one to express 'placed' values in a chain? |
This has always been a bit of an issue.
ttt-style vertical notation is the most explicit but takes forever to compose and makes the eyes of most readers glaze over.
Asterisks and bold-face have been used, but require a footnote. |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Sun Jul 04, 2010 4:03 pm Post subject: |
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| peterj wrote: | | Is there a notation which allows one to express 'placed' values in a chain? |
I'm not aware of any, other than ttt's, that are still in use. When Jeff wrote about Forcing Chains, he used a notation that works for simple networks where eliminations were carried forward by enclosing them in parentheses. Here's a simple network stream with the notation Jeff used.
r2c2<>5 r2c8=5 r9c8<>5 r9c9=5 (r9c9<>2) r9c9<>1 r9c7=1 r9c7<>2 r8c79=2 r8c3<>2
I would write this stream using a compact variation on an old branching and merging notation. It allows AIC notation, but it's still cumbersome and doesn't work with complex networks.
| Code: | -------------------
/ \
(5)r2c2 = r2c8 - r9c8 = (5-21)r9c9 = (1-2)r9c7 = r8c79 - (2)r8c3
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I can understand why ALS notation is so popular. It allows many network scenarios to be expressed as a single term in a chain. |
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ttt
Joined: 06 Dec 2008
Posts: 42
Location: vietnam
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| Posted: Mon Jul 05, 2010 4:45 pm Post subject: |
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| Code: | *-----------------------------------------------------------------------------*
| 89 45 7 | 4689 1489 14689 | 3 2 4589 |
| 1 345 34 | 2 489 7 | 489 589 6 |
| 89 2 6 | 3489 5 3489 | 7 1 489 |
|-------------------------+-------------------------+-------------------------|
| 347 8 345 | 3459 1349 2 | 1469 3679 1349 |
| 2347 1 9 | 348 6 348 | 5 378 2348 |
| 234 6 2345 | 7 13489 134589 | 12489 389 123489 |
|-------------------------+-------------------------+-------------------------|
| 36 9 1 | 3568 2 3568 | 68 4 7 |
| 5 34 234 | 1 7 34689 | 2689 3689 2389 |
| 2346 7 8 | 3469 349 3469 | 1269 3569 12359 |
*-----------------------------------------------------------------------------* |
Hmm...!
I was surprised: why nobody considers HP(12) on R9?
AUR(34)r28c23:[(5)r2c2=(2)r8c3]-(2)r9c1=(12-5)r9c79=(5)r9c8 => r2c8<>5
ttt |
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