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daj95376
Joined: 23 Aug 2008
Posts: 3854
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 Posted: Tue Nov 17, 2009 4:55 pm Post subject: Puzzle NR 09/11/17 (B) |
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| Code: | +-----------------------+
| 8 . . | 5 6 . | 4 7 . |
| . 7 . | 1 . 4 | . 5 . |
| . . 6 | . . 7 | 1 . . |
|-------+-------+-------|
| 4 5 . | . 9 3 | . . . |
| 1 . . | 6 5 . | . . . |
| . 3 2 | 4 . 1 | . . . |
|-------+-------+-------|
| 2 . 4 | . . . | 3 . . |
| 3 1 . | . . . | . 4 . |
| . . . | . . . | . . 5 |
+-----------------------+
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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: Tue Nov 17, 2009 7:24 pm Post subject: |
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Cool!  |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Wed Nov 18, 2009 7:36 pm Post subject: |
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Dan,
I would appreciate some details on your solution.
Ted |
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arkietech
Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA
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| Posted: Wed Nov 18, 2009 10:11 pm Post subject: |
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| tlanglet wrote: | | I would appreciate some details on your solution. |
| Code: | *--------------------------------------------------------------------*
| 8 2 1 | 5 6 9 | 4 7 3 |
| 9 7 3 | 1 28 4 | 268 5 268 |
| 5 4 6 | 28 3 7 | 1 289 289 |
|----------------------+----------------------+----------------------|
| 4 5 78 | 278 9 3 | 2678 268 1 |
| 1 *9-8 *789 | 6 5 28 | 278 3 4 |
| 6 3 2 | 4 78 1 | 5 89 789 |
|----------------------+----------------------+----------------------|
| 2 689 4 | 789 1 5 | 3 68 678 |
| 3 1 5 | 2789 278 268 | 26789 4 2678 |
| 7 *689 *9-8 | 3 4 268 | 2689 1 5 |
*--------------------------------------------------------------------*
First ur 89 I believe it is type 6
This leads to
*--------------------------------------------------*
| 8 2 1 | 5 6 9 | 4 7 3 |
| 9 7 3 | 1 28 4 | 268 5 268 |
| 5 4 6 | 8-2 3 7 | 1 *289 *289 |
|----------------+----------------+----------------|
| 4 5 78 | 28 9 3 | 267 26 1 |
| 1 9 78 | 6 5 28 | 27 3 4 |
| 6 3 2 | 4 7 1 | 5 *89 *89 |
|----------------+----------------+----------------|
| 2 68 4 | 9 1 5 | 3 68 7 |
| 3 1 5 | 7 28 268 | 9 4 268 |
| 7 68 9 | 3 4 268 | 268 1 5 |
*--------------------------------------------------*
Second ur 89
singles to finish |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Wed Nov 18, 2009 10:57 pm Post subject: |
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| arkietech wrote: |
| Code: | *--------------------------------------------------------------------*
| 8 2 1 | 5 6 9 | 4 7 3 |
| 9 7 3 | 1 28 4 | 268 5 268 |
| 5 4 6 | 28 3 7 | 1 289 289 |
|----------------------+----------------------+----------------------|
| 4 5 78 | 278 9 3 | 2678 268 1 |
| 1 *9-8 *789 | 6 5 28 | 278 3 4 |
| 6 3 2 | 4 78 1 | 5 89 789 |
|----------------------+----------------------+----------------------|
| 2 689 4 | 789 1 5 | 3 68 678 |
| 3 1 5 | 2789 278 268 | 26789 4 2678 |
| 7 *689 *9-8 | 3 4 268 | 2689 1 5 |
*--------------------------------------------------------------------*
First ur 89 I believe it is type 6
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Dan,
I also saw the type 6 UR 89, but the only deletion I made was r9c2<>9 due to the strong link on 9 in row5 and col3.
What is the specific logic/reasoning that allowed you to delete 8 in r5c2 and r9c3?
Ted |
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Mogulmeister
Joined: 03 May 2007
Posts: 1151
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| Posted: Wed Nov 18, 2009 11:45 pm Post subject: |
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Dan,
I think that this may not be a proper type 6 UR.
"Suppose exactly two cells in the rectangle contain extra candidates, and they are located diagonally across each other in the rectangle. Suppose the common candidates are U and V, and none of the other cells in the two rows and two columns containing the rectangle contain U. Then U can be eliminated from these two cells."
Unfortunately there are other 8s that spoil the party.
You can prove this by dropping in 8's into your proposed elimination squares - you can't create the deadly pattern. |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Thu Nov 19, 2009 12:05 am Post subject: |
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After three ERs, the 89 UR in boxes 36 was a Type 2 which finished things off.
Hey MM, welcome back after your two-year sabbatical!!  |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Thu Nov 19, 2009 12:22 am Post subject: |
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Sorry Dan,
The <9> at r9c7 ruins the X-Wing you need for your UR Type 6.
However, the puzzle can be solved in two steps:
Skyscraper on <7> followed by <89> UR r36c89 Type 2. |
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arkietech
Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA
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| Posted: Thu Nov 19, 2009 1:38 am Post subject: |
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| daj95376 wrote: | Sorry Dan,
The <9> at r9c7 ruins the X-Wing you need for your UR Type 6.
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Oh shucks -- back to the pedia  |
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Mogulmeister
Joined: 03 May 2007
Posts: 1151
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| Posted: Thu Nov 19, 2009 6:28 am Post subject: |
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| Many thanks Marty! |
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oaxen
Joined: 10 Jul 2006
Posts: 96
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| Posted: Fri Nov 20, 2009 10:44 am Post subject: |
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| a "7" in r5c3 makes it a one stepper |
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