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daj95376
Joined: 23 Aug 2008
Posts: 3854
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 Posted: Thu Jan 28, 2010 8:21 pm Post subject: Puzzle 10/01/28 (C) |
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Single-stepper as a chain.
| Code: | +-----------------------+
| . . . | . . . | 5 1 . |
| . 2 . | 5 8 . | . . . |
| . . 7 | . 1 4 | . . 9 |
|-------+-------+-------|
| . 3 . | 7 . . | 9 . 4 |
| . 7 9 | . 3 . | . . . |
| . . 1 | . . 8 | . . . |
|-------+-------+-------|
| 3 . . | 8 . . | . 9 . |
| 5 . . | . . . | 3 . . |
| . . 8 | 9 . . | . . 1 |
+-----------------------+
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Play this puzzle online at the Daily Sudoku site |
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arkietech
Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA
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| Posted: Fri Jan 29, 2010 2:32 am Post subject: |
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Bingo! | Quote: | (2=3)r3c8-(3)r3c4=(3-6)r1c4=(6)r5c4-(6=2)r5c9
=> r1c9,r45c8<>2 |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Fri Jan 29, 2010 5:13 pm Post subject: |
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Single-stepper as a chain, but not needed to solve the puzzle.
(A present for the chain lovers!) |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Fri Jan 29, 2010 6:07 pm Post subject: |
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I'm getting nowhere. After two URs, M-Wing with pincer transport, XY-Chain and Finned X-Wing, I find myself stuck here. I'm pretty sure I could break it with Medusa but I think there's something here that I can't spot but should.
| Code: |
+---------+-------------+-------------+
| 9 8 4 | 36 7 26 | 5 1 23 |
| 1 2 3 | 5 8 9 | 46 47 67 |
| 6 5 7 | 23 1 4 | 8 23 9 |
+---------+-------------+-------------+
| 28 3 5 | 7 26 1 | 9 68 4 |
| 48 7 9 | 46 3 5 | 1 268 268 |
| 24 6 1 | 24 9 8 | 7 35 35 |
+---------+-------------+-------------+
| 3 1 26 | 8 2456 267 | 246 9 567 |
| 5 9 26 | 1 246 267 | 3 478 678 |
| 7 4 8 | 9 256 3 | 26 256 1 |
+---------+-------------+-------------+
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Fri Jan 29, 2010 7:17 pm Post subject: |
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| Marty R. wrote: | I'm getting nowhere.
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My solver doesn't like your grid.
| Code: | +--------------------------------------------------------------+
| 9 8 4 | 36 7 26 | 5 1 23 |
| 1 2 3 | 5 8 9 | 46 47 67 |
| 6 5 7 | 23 1 4 | 8 23 9 |
|--------------------+--------------------+--------------------|
| 28 3 5 | 7 26 1 | 9 68 4 |
| 48 7 9 | 46 3 5 | 1 268 268 |
| 24 6 1 | 24 9 8 | 7 35 35 |
|--------------------+--------------------+--------------------|
| 3 1 26 | 8 2456 267 | 246 9 567 |
| 5 9 26 | 1 246 267 | 3 478 678 |
| 7 4 8 | 9 256 3 | 26 256 1 |
+--------------------------------------------------------------+
# 45 eliminations remain
_start Givens:
...
_end Givens:
*** ERROR: candidate <2> missing from solution -- [r1c4] ***
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The incorrect elimination r1c4<>2 seems to be the only thing holding you back. |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Sat Jan 30, 2010 1:12 am Post subject: |
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I have not yet found the one-stepper, but did fine an interesting solution.
Two parts for a UR28 in r45c18.
First, to prevent the deadly pattern:
(6)r45c8 - (6=5)r9c8 - (5=3)r6c8 - (3=2)r3c8 - r1c9= (2)r5c9,
(4)r5c1 - (4=2)r6c1,
These two pincers delete 2 from r5c1.
Part 2 of UR28 in r45c18 has a x-wing 8 overlay which deletes 2 from r5c8.
So, different conditions impacting the same pattern provided different deletions. Does this count as one move or two?
Simple coloring on 2 now completes the puzzle.
Ted |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Sat Jan 30, 2010 2:03 am Post subject: |
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| tlanglet wrote: | I have not yet found the one-stepper, but did fine an interesting solution.
Two parts for a UR28 in r45c18.
First, to prevent the deadly pattern:
(6)r45c8 - (6=5)r9c8 - (5=3)r6c8 - (3=2)r3c8 - r1c9= (2)r5c9,
(4)r5c1 - (4=2)r6c1,
These two pincers delete 2 from r5c1.
Part 2 of UR28 in r45c18 has a x-wing 8 overlay which deletes 2 from r5c8.
So, different conditions impacting the same pattern provided different deletions. Does this count as one move or two?
Simple coloring on 2 now completes the puzzle.
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Five moves ... because your DP logic was excessive!
| Code: | *--------------------------------------------------------------------*
| 9 8 4 | 236 267 267 | 5 1 23 |
| 1 2 3 | 5 8 9 | 46 47 67 |
| 6 5 7 | 23 1 4 | 8 23 9 |
|----------------------+----------------------+----------------------|
| 28 3 5 | 7 26 1 | 9 268 4 |
| 248 7 9 | 246 3 5 | 1 268 26 |
| 24 6 1 | 24 9 8 | 7 35 35 |
|----------------------+----------------------+----------------------|
| 3 1 26 | 8 24567 267 | 246 9 567 |
| 5 9 26 | 1 2467 267 | 3 47 8 |
| 7 4 8 | 9 256 3 | 26 56 1 |
*--------------------------------------------------------------------*
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(6)r45c8 - (6=2)r5c9 - (2)r5c1,
(4-2)r5c1
It was fun ribbing you. 
Regards, Danny |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Sat Jan 30, 2010 2:21 am Post subject: |
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It is my understanding that "a valid deletion is a deletion at any time". What I mean is that if a deletion is valid based on a pattern at a given stage, then it is still valid at a later stage when the original pattern may be destroyed.
Using this approach I have another two-stepper.
UR 24 in r56c14 with x-wing 4 overlay that deletes 2 from r5c14.
However , if the deletion is not taken immediately then another pattern is useful that involves cell r5c1.
Hidden UR28 r45c18 with x-wing 8 overlay deletes 2 from r5c8.
If all deletions are now taken, the 2 in r5c9 becomes a single in row5 and the puzzle is solved.
Comments???
Ted |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Sat Jan 30, 2010 2:29 am Post subject: |
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| daj95376 wrote: |
Five moves ... because your DP logic was excessive!
| Code: | *--------------------------------------------------------------------*
| 9 8 4 | 236 267 267 | 5 1 23 |
| 1 2 3 | 5 8 9 | 46 47 67 |
| 6 5 7 | 23 1 4 | 8 23 9 |
|----------------------+----------------------+----------------------|
| 28 3 5 | 7 26 1 | 9 268 4 |
| 248 7 9 | 246 3 5 | 1 268 26 |
| 24 6 1 | 24 9 8 | 7 35 35 |
|----------------------+----------------------+----------------------|
| 3 1 26 | 8 24567 267 | 246 9 567 |
| 5 9 26 | 1 2467 267 | 3 47 8 |
| 7 4 8 | 9 256 3 | 26 56 1 |
*--------------------------------------------------------------------*
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(6)r45c8 - (6=2)r5c9 - (2)r5c1,
(4-2)r5c1
It was fun ribbing you.
Regards, Danny |
I am usually just groping for a solution, long or short, simple or a mess. Also, I find myself normally looking for solutions based on what a cell value "is", not on what it "is not". In this case, the "is not" is obviously cleaner.
Thanks Danny,
Ted |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Sat Jan 30, 2010 2:41 am Post subject: |
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| tlanglet wrote: | It is my understanding that "a valid deletion is a deletion at any time". What I mean is that if a deletion is valid based on a pattern at a given stage, then it is still valid at a later stage when the original pattern may be destroyed.
Using this approach I have another two-stepper.
UR 24 in r56c14 with x-wing 4 overlay that deletes 2 from r5c14.
However , if the deletion is not taken immediately then another pattern is useful that involves cell r5c1.
Hidden UR28 r45c18 with x-wing 8 overlay deletes 2 from r5c8.
If all deletions are now taken, the 2 in r5c9 becomes a single in row5 and the puzzle is solved.
Comments???
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I just finished checking this out for myself and was going to report the same results. Place the blue line before the green line and you don't need to include the intro.
As for the intro, you are essentially correct. If a candidate was ever present in a cell, then it can be used in UR logic even after it's been deleted in an earlier step. Boy did I have fun with that the first time I hear it!!!
Regards, Danny
BTW: Sorry for the ribbing. I'm tired! |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Sat Jan 30, 2010 5:58 am Post subject: |
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| Quote: | | My solver doesn't like your grid. |
I don't like my grid.  |
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