Need help understanding why UR Type 3 does not work here

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Need help understanding why UR Type 3 does not work here

Postby mrzappit » Wed May 13, 2020 1:00 pm

Code: Select all
.-----------.------------------.--------------.
| 9  4   6  | 8     235    23  | 35   1   7   |
| 1  25  3  | 569   59     7   | 4    26  8   |
| 7  25  8  | 4     1      356 | 359  26  59  |
:-----------+------------------+--------------:
| 8  1   47 | 3579  47359  35  | 2    39  6   |
| 2  3   47 | 679   4789   16  | 18   5   49  |
| 5  6   9  | 23    2348   123 | 18   7   34  |
:-----------+------------------+--------------:
| 3  79  25 | 27    6      4   | 59   8   1   |
| 4  79  25 | 1     27     8   | 6    39  359 |
| 6  8   1  | 35    35     9   | 7    4   2   |
'-----------'------------------'--------------'


I am using the Unique Rectangle Type 3 method found here: http://hodoku.sourceforge.net/en/tech_ur.php#u3

What I am seeing is that I have a UR Type 3 on 4/7 in Rows 4 & 5 in Columns 3 & 5. That should leave me trying to find a Naked Subset for 3, 5, 8, and 9 in column 4. I have found that using the cells in rows 2, 4, 5, and 9. So, shouldn't that mean that I can eliminate 3, 5, 8, and 9 from all cells in column 5 that are not in rows 2, 4, 5, or 9? I would think that would mean that I can eliminate the 3 and 5 from row 1 column 5, but that leads to errors. Any help would be greatly appreciated.
mrzappit
 
Posts: 1
Joined: 13 May 2020

Re: Need help understanding why UR Type 3 does not work here

Postby yzfwsf » Tue Jun 02, 2020 5:26 am

mrzappit wrote:What I am seeing is that I have a UR Type 3 on 4/7 in Rows 4 & 5 in Columns 3 & 5. That should leave me trying to find a Naked Subset for 3, 5, 8, and 9 in column 4. I have found that using the cells in rows 2, 4, 5, and 9. So, shouldn't that mean that I can eliminate 3, 5, 8, and 9 from all cells in column 5 that are not in rows 2, 4, 5, or 9? I would think that would mean that I can eliminate the 3 and 5 from row 1 column 5, but that leads to errors. Any help would be greatly appreciated.

First there is a typo 4 -> 5.
In UR type 3 ,the two ur cells(r45c5) form 1 virtual cell, hence you have a ALS,not a Naked quad.
yzfwsf
 
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Joined: 16 April 2019


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