To UR3 or not to UR3

Post the puzzle or solving technique that's causing you trouble and someone will help

To UR3 or not to UR3

Postby civiliza » Tue Jul 26, 2011 11:05 am

Running my generator today, I came across a puzzle that Sudoku Explainer reckons can be solved with a Type 3 Unique Rectangle.

Trouble is that my Generator only recognises Type 1 Unique Rectangles.

By forcing Sudoku Explainer to keep suggesting alternative methods, I found out how my Generator came up with this puzzle without using Type 3 UR's, but can you?

Code: Select all
601030970
000020450
000000001
018970600
920000040
007000100
000005060
009760014
006300000
civiliza
 
Posts: 64
Joined: 25 October 2010

Re: To UR3 or not to UR3

Postby daj95376 » Tue Jul 26, 2011 2:58 pm

You should consider finding an alternative to Sudoku Explainer for solving puzzles.

Code: Select all
 after basics: concurrent URs
 +-----------------------------------------------------------------------+
 |  6      458    1      |  458    3      48     |  9      7      2      |
 |  78     789    3      |  18     2      179    |  4      5      6      |
 |  257    4579   24     |  456    459    679    |  8      3      1      |
 |-----------------------+-----------------------+-----------------------|
 | *34     1      8      |  9      7     *34     |  6      2      5      |
 |  9      2      5      |  168    18     16     |  37     4      37     |
 | *34     6      7      |  245    45    *34+2   |  1     *89    *89     |
 |-----------------------+-----------------------+-----------------------|
 |  1278   3478   24     |  1248   1489   5      |  237    6      3789   |
 |  258    358    9      |  7      6      28     |  235    1      4      |
 |  12578  4578   6      |  3      1489   19     |  257   *89    *89+7   |
 +-----------------------------------------------------------------------+
 # 80 eliminations remain

 r69c89  <89> UR Type 1.2223             <> 89   r9c9
 r46c16  <34> UR Type 1.2223             <> 34   r6c6
daj95376
2014 Supporter
 
Posts: 2624
Joined: 15 May 2006

Re: To UR3 or not to UR3

Postby ronk » Tue Jul 26, 2011 3:33 pm

daj95376 wrote:You should consider finding an alternative to Sudoku Explainer for solving puzzles.

Using a UR Type 4 in this puzzle, as Explainer does, is not so bad. It bypasses the need for a naked quad or hidden quad.
ronk
2012 Supporter
 
Posts: 4764
Joined: 02 November 2005
Location: Southeastern USA

Re: To UR3 or not to UR3

Postby m_b_metcalf » Tue Jul 26, 2011 4:08 pm

Please note that the puzzle has three redundant clues.

Regards,

Mike Metcalf
User avatar
m_b_metcalf
2017 Supporter
 
Posts: 8363
Joined: 15 May 2006
Location: Berlin


Return to Help with puzzles and solving techniques