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daj95376
Joined: 23 Aug 2008
Posts: 3854
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 Posted: Sat Nov 07, 2009 8:02 pm Post subject: Puzzle NR 09/11/07 |
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| Code: | NR puzzles can be solved using these 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
VH+: 2-String Kite, Empty Rectangle, Remote Pair, Skyscraper,
XYZ-Wing, finned X-Wing, UR Type 2/4
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| Code: | +-----------------------+
| 3 . . | . . . | . 4 7 |
| . . 8 | 7 . . | 1 . . |
| . 6 . | . 8 2 | 9 . . |
|-------+-------+-------|
| . 2 . | . . . | . 8 . |
| . . 9 | . . . | . . 3 |
| . . 3 | . . . | 5 . . |
|-------+-------+-------|
| . 8 7 | . . 9 | . . 6 |
| 9 . . | 8 . . | . 5 . |
| 2 . . | . 1 . | 4 . . |
+-----------------------+
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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: Sat Nov 07, 2009 11:08 pm Post subject: |
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A one step solution:
| Quote: | A type 3 UR 17 in r56c28 deletes 5 in r1c2
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Ted |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Sat Nov 07, 2009 11:41 pm Post subject: |
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| Congratulations Ted!!! A UR type not currently supported by my solver. |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Sun Nov 08, 2009 12:47 am Post subject: |
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| Maybe I made a mistake or maybe I got something extra eliminated during basics, but, at any rate, that was a Type 1 when I got to it. |
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arkietech
Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA
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| Posted: Sun Nov 08, 2009 8:31 am Post subject: |
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Looks like a type 3 to me?  | Code: | *--------------------------------------------------------------------*
| 3 1-5 2 | 1569 569 156 | 8 4 7 |
| 45 9 8 | 7 3 45 | 1 6 2 |
| 7 6 14 | 14 8 2 | 9 3 5 |
|----------------------+----------------------+----------------------|
| 45 2 145 | 13459 7 1345 | 6 8 49 |
| 68 17(45 9 | 1456 456 14568 | 2 17 3 |
| 68 17(4 3 | 2 469 1468 | 5 17 49 |
|----------------------+----------------------+----------------------|
| 1 8 7 | 45 45 9 | 3 2 6 |
| 9 34 46 | 8 2 36 | 7 5 1 |
| 2 35 56 | 36 1 7 | 4 9 8 |
*--------------------------------------------------------------------*
r56c2=4; r8c2=3; r9c2=5 => r1c2<>5
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Sun Nov 08, 2009 4:42 pm Post subject: |
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My solver found it as <17> UR Type 4. That's of little importrance.
What I am wondering is why the eliminations for the UR Type 3 didn't include r4c3<>45. |
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storm_norm
Joined: 18 Oct 2007
Posts: 1741
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| Posted: Sun Nov 08, 2009 6:01 pm Post subject: |
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| the other way to look at the UR 17 is to see that the only 1 or 7 in columns 2 and 8 are in 5 places. the UR cells and r1c2. which means that in order to avoid the UR, as far as the columns are concerned is in r1c2. which has to be a 1 to avoid it. |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Mon Nov 09, 2009 12:34 am Post subject: |
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| storm_norm wrote: | | the other way to look at the UR 17 is to see that the only 1 or 7 in columns 2 and 8 are in 5 places. the UR cells and r1c2. which means that in order to avoid the UR, as far as the columns are concerned is in r1c2. which has to be a 1 to avoid it. |
And, as far as [box 4] is concerned, r4c3=1. |
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storm_norm
Joined: 18 Oct 2007
Posts: 1741
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| Posted: Mon Nov 09, 2009 1:12 am Post subject: |
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| daj95376 wrote: | | storm_norm wrote: | | the other way to look at the UR 17 is to see that the only 1 or 7 in columns 2 and 8 are in 5 places. the UR cells and r1c2. which means that in order to avoid the UR, as far as the columns are concerned is in r1c2. which has to be a 1 to avoid it. |
And, as far as [box 4] is concerned, r4c3=1. |
absolutely.
so instead of looking for the type 3 logic, with finding the subsets involved in the UR cells.
it might be easier to isolate the UR candidate in each house and see where the outlets are. if there is only one outlet for a candidate then that would be an easier place to start. |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Mon Nov 09, 2009 1:24 am Post subject: |
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| daj95376 wrote: |
What I am wondering is why the eliminations for the UR Type 3 didn't include r4c3<>45. |
Danny,
I viewed this UR as a type 3 where I combined the extra UR pseudocell digits, 45, with the two bivalue cells in r2c89 to form a 345 subset. Since the subset resided in col2, the only deletion was r2c1. Yes, I later realized the 45 naked pair also exists in box4, but I missed it initially when I made my post.
Ted |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Mon Nov 09, 2009 5:05 pm Post subject: |
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| tlanglet wrote: | | daj95376 wrote: |
What I am wondering is why the eliminations for the UR Type 3 didn't include r4c3<>45. |
Danny,
I viewed this UR as a type 3 where I combined the extra UR pseudocell digits, 45, with the two bivalue cells in r2c89 to form a 345 subset. Since the subset resided in col2, the only deletion was r2c1. Yes, I later realized the 45 naked pair also exists in box4, but I missed it initially when I made my post.
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Good!!!
For the longest time, I missed important eliminatons with URs Type 3 because I failed to catch the interaction within the box as well as in the row/column. I wanted to bring the [box 4] eliminations out into the light.
Regards, Danny |
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