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daj95376
Joined: 23 Aug 2008
Posts: 3854
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 Posted: Sat Dec 05, 2009 7:46 pm Post subject: Puzzle NR 09/12/06 (B) |
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| Code: | +-----------------------+
| 2 . . | 6 . . | . . 9 |
| . 9 . | 1 . 4 | . 7 . |
| . . . | . . . | 6 2 . |
|-------+-------+-------|
| 4 5 . | 2 . . | 8 . . |
| . . . | . 7 . | . 1 5 |
| . 7 . | . . 1 | . . . |
|-------+-------+-------|
| . . 2 | 7 . . | 1 . . |
| . 8 7 | . 1 . | . 5 . |
| 1 . . | . 8 . | . . 2 |
+-----------------------+
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Play this puzzle online at the Daily Sudoku site |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Sun Dec 06, 2009 4:58 pm Post subject: |
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Danny, from my viewpoint you have exceeded your degree of BBDB puzzles  I guess the new level is BBDB+, which is for 10 or more steps.
Taking the deletions as they came, I used thirteen (yes, 13) steps to complete the puzzle. Some were easy to spot, some were definitely not.
Mostly I deleted the digit 3 but also 4 and 9. I used ERs, kites, skyscrapers, y-wings, xy-wings, and chains found by extending the potential vertex of potential xy-wings. I completed the puzzle with a Type 1 UR.
Congratulations...............
Ted |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Sun Dec 06, 2009 6:30 pm Post subject: |
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Ted, I know that my puzzles have been harder lately, but I never intended for anyone to encounter difficulties like you experienced. My solver listed five steps (and two extraneous).
| Code: | r1 b3 Locked Candidate 1 <> 4 r1c3
r3 b2 Locked Candidate 1 <> 8 r3c3
c2b7 Locked Candidate 2 <> 6 r78c1,r9c3
c59 X-Wing <> 4 r6c48,r7c28 -or-
r58 X-Wing <> 4 r69c4,r1c7
c7b3 Locked Pair <> 35 r58c7
XY-Wing r8c7/r7c9+r8c1 <> 3 r7c12
r5 b4 Locked Candidate 2 <> 6 r6c13
r8c2 2-String Kite <> 3 r3c4 extraneous
c9b8 Empty Rectangle <> 3 r6c4 extraneous
c16r7 Skyscraper (Sashimi X-Wing) <> 5 r3c3
r3 b1 Locked Pair <> 34 r2c13,r3c56
r47c6 Skyscraper <> 3 r6c9,r9c8
r39c23 <34> UR Type 1 <> 34 r9c3
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I'll search my files for less complex puzzles (and generate new ones as well).
Regards, Danny |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Sun Dec 06, 2009 8:14 pm Post subject: |
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| daj95376 wrote: | Ted, I know that my puzzles have been harder lately, but I never intended for anyone to encounter difficulties like you experienced. My solver listed five steps (and two extraneous).
I'll search my files for less complex puzzles (and generate new ones as well).
Regards, Danny |
Danny, please do not misunderstand my post. I enjoyed this puzzle! I simply took every move I saw even when I was fairly sure it was not a productive deletion, and was surprised/impressed that it took me so many steps.
This recent series has taken lots of steps but they are mostly VH & some VH+ techniques. I believe that a large majority of the folks that follow the dailysudoku forums could solve them. And, of course, the number of steps required is strongly dependent on the sequence of patterns being investigated; this puzzle is a prime example of that situation.
Ted  |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Sun Dec 06, 2009 8:49 pm Post subject: |
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| tlanglet wrote: | | Danny, please do not misunderstand my post. I enjoyed this puzzle! |
I did misunderstand. Thank you for clarifying!!!
I know that many of my puzzles demand a lot from those solving them, and I'm always concerned that some will produce a negative response because a moderate step (for my solver) was missed and caused turmoil.
Even though you enjoyed the puzzle, I do believe that I should add some less demanding puzzles to the mix to provide a relief while still providing a challenge. Ironically, my puzzle generator doesn't seem to generate many puzzles in this middle ground -- either too easy or several steps.
I'll keep an eye out for puzzles that provide some relief from BBDB and BBDB+. In particular, I'll reduce the number of single-digit patterns because I know that, when one is present, then others are often present that aren't productive.
Regards, Danny
Note: I try to avoid having colors/XY-Wing/XYZ-Wing be the last step in a puzzle. Turns out, my puzzle generator hates passing over these final steps. |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Sun Dec 06, 2009 11:10 pm Post subject: |
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Danny,
I had 11 steps, including an elaborate coloring on 3 that maybe counts as more than one step. I think the SS on 5 is the key to fewer steps.
An SS on 5 was my last step. You can spend a lot of time chipping away at 3 and 9.
Keith |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Sun Dec 06, 2009 11:44 pm Post subject: |
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| keith wrote: | Danny,
I had 11 steps, including an elaborate coloring on 3 that maybe counts as more than one step. I think the SS on 5 is the key to fewer steps.
An SS on 5 was my last step. You can spend a lot of time chipping away at 3 and 9.
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Hello Keith,
Yes, it's my opinion that the Skyscraper on <5> was key to opening up the UR Type 1 that my solver used to crack the puzzle. Yes again, only a few of the <3> eliminations were important. However, since there wasn't a <3> in the clues/givens provided, I expect that finding them might be an effort.
I think the important thing is that I didn't heed the variety of alternate solutions I examined. Otherwise, I might have noticed there were a number of alternative steps that could send someone off on an unproductive tangent -- like a second XY-Wing and a UR type 4.
Unfortunately, I don't have a way of projecting the worst case scenario for a puzzle's solution, but I'll do what I can to prevent puzzles like this in the future.
Regards, Danny |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Mon Dec 07, 2009 1:07 am Post subject: |
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Danny,
I have no complaints about the puzzle!
Keith |
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oaxen
Joined: 10 Jul 2006
Posts: 96
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| Posted: Mon Dec 07, 2009 9:24 am Post subject: |
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Thank you Danny. A good puzzle.
With the simplified Oaxen method I needed two steps. "4:s" on row 5 looks interesting. It worked out to be r5c4. Then a 6 in r4c8 gives the final answer. |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Tue Dec 08, 2009 4:34 pm Post subject: |
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| I'm the winner: 15 steps!! I finished up with a Skyscraper on 5 and a W-Wing on 35. Had I looked for Skyscrapers earlier I might have saved some steps. But, like Ted, I enjoyed the puzzle. I like BBDBs as long as the puzzle can be solved with steps in my arsenal, which isn't as large as it ought to be. |
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