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Extremely Difficult Sudolu Puzzle (at least for me)

 
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dongrave



Joined: 06 Mar 2014
Posts: 54

PostPosted: Thu Jun 05, 2014 10:55 pm    Post subject: Extremely Difficult Sudolu Puzzle (at least for me) Reply with quote

Hi Marty, Here's the Sudoku that I mentioned in my post earlier today on the 'Daily Sudoku Puzzles' Discussion page. I was able to fill in the first 10 squares but then I came to a complete standstill. I found no way of proceeding using either basic processing or any of the standard advanced techniques (i.e. x-wing, xy-wing, xyz-wing, or URL). Do you see a way to proceed? I spent a long looking after the 1st 10 squares and all that I was able to find was one xyz-wing that eliminated one candidate from one box. Help! I don't see it any way to proceed after the 1st 10 squares!

9 0 4 0 3 0 0 0 5
7 0 0 2 0 0 6 0 0
0 0 0 0 0 5 0 0 0

0 0 3 0 0 1 9 0 6
0 1 0 0 9 0 0 8 0
5 0 9 7 0 0 3 0 0

0 0 0 6 0 0 0 0 0
0 0 2 0 0 8 0 0 7
3 0 0 0 1 0 2 0 9

If you want, I can provide you with the position I that reached but I'm sure that you'll reach it easily enough so I won't bother. As I mentioned in my earlier post today (on the other page), this puzzle was from a recent local newspaper. I have done their puzzles before and none of them have ever been anywhere near this difficult so I suspect that either I'm missing something or they misprinted the puzzle! Thanks, Don.
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Marty R.



Joined: 12 Feb 2006
Posts: 5164
Location: Rochester, NY, USA

PostPosted: Thu Jun 05, 2014 11:46 pm    Post subject: Reply with quote

Code:

+-------+-------+-------+
| 9 . 4 | . 3 . | . . 5 |
| 7 . . | 2 . . | 6 . . |
| . . . | . . 5 | . . . |
+-------+-------+-------+
| . . 3 | . . 1 | 9 . 6 |
| . 1 . | . 9 . | . 8 . |
| 5 . 9 | 7 . . | 3 . . |
+-------+-------+-------+
| . . . | 6 . . | . . . |
| . . 2 | . . 8 | . . 7 |
| 3 . . | . 1 . | 2 . 9 |
+-------+-------+-------+

Play this puzzle online at the Daily Sudoku site

Don, you might want to read the article about posting an aligned grid in the Site Help sub-forum if you expect to post more puzzles.
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Marty R.



Joined: 12 Feb 2006
Posts: 5164
Location: Rochester, NY, USA

PostPosted: Fri Jun 06, 2014 12:00 am    Post subject: Reply with quote

I did a very quick attempt at basics online and came up with the following. I'll try doing the puzzle a little later.

Code:

+-------------+-------------+-----------------+
| 9   2    4  | 18  3   6   | 178  17    5    |
| 7   35   15 | 2   48  49  | 6    1349  1348 |
| 8   36   16 | 149 7   5   | 14   12349 1234 |
+-------------+-------------+-----------------+
| 2   47   3  | 458 458 1   | 9    57    6    |
| 46  1    67 | 345 9   234 | 57   8     24   |
| 5   8    9  | 7   6   24  | 3    124   124  |
+-------------+-------------+-----------------+
| 14  4579 57 | 6   2   39  | 1458 1345  1348 |
| 146 4569 2  | 39  45  8   | 145  13456 7    |
| 3   456  8  | 45  1   7   | 2    456   9    |
+-------------+-------------+-----------------+

Play this puzzle online at the Daily Sudoku site
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arkietech



Joined: 31 Jul 2008
Posts: 1727
Location: Northwest Arkansas USA

PostPosted: Fri Jun 06, 2014 12:13 am    Post subject: Reply with quote

Code:
There are 2 big almost locked sets one in row 5 and one in row 7 that will remove the candidate 3 in r7c6
 *--------------------------------------------------------------------*
 | 9      2      4      | 18     3      6      | 178    17     5      |
 | 7      35     15     | 2      48     49     | 6      1349   1348   |
 | 8      36     16     | 149    7      5      | 14     12349  1234   |
 |----------------------+----------------------+----------------------|
 | 2      47     3      | 458    458    1      | 9      57     6      |
 |a46     1     a67     | 345    9     a234    | 57     8     a24     |
 | 5      8      9      | 7      6      24     | 3      124    124    |
 |----------------------+----------------------+----------------------|
 |b14     4579  b57     | 6      2      9-3    |b1458  b1345  b1348   |
 | 146    4569   2      | 39     45     8      | 145    13456  7      |
 | 3      456    8      | 45     1      7      | 2      456    9      |
 *--------------------------------------------------------------------*
(3=2467)r5c1369-(7=14583)r7c13789 => -3r7c6; ste
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Marty R.



Joined: 12 Feb 2006
Posts: 5164
Location: Rochester, NY, USA

PostPosted: Fri Jun 06, 2014 1:34 am    Post subject: Reply with quote

Quote:
I found no way of proceeding using either basic processing or any of the standard advanced techniques (i.e. x-wing, xy-wing, xyz-wing, or URL). Do you see a way to proceed? I spent a long looking after the 1st 10 squares and all that I was able to find was one xyz-wing that eliminated one candidate from one box.


Don,

The grids you see posted by Dan and me have taken basics as far as possible. I can find no X-, XY- or XYZ-Wings or helpful URs. Plus I missed the XYZ-Wing that you played. To complete this puzzle, chains will be required, such as the one that Dan posted.

This is a pretty tough puzzle for a newspaper.
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dongrave



Joined: 06 Mar 2014
Posts: 54

PostPosted: Fri Jun 06, 2014 2:01 am    Post subject: Reply with quote

Thanks for the input guys! I guess it's time for me to learn some of the more advanced techniques. I think the newspaper must have misprinted this though because I've never had to use wings or chains or cycles to solve any of their puzzles before. Also, thanks for directing me to the help page for posting grids. I'll be sure to do that from now on. I'm pretty sure the poor girl at work will be glad tomorrow to hear what you said about this being an awful difficult puzzle for a newspaper. Thanks again, Don.
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Pat



Joined: 23 Feb 2010
Posts: 165

PostPosted: Sun Jun 08, 2014 10:48 am    Post subject: Reply with quote

dongrave wrote:
    9.4.3...57..2..6.......5.....3..19.6.1..9..8.5.97..3.....6.......2..8..73...1.2.9

maybe r9c1 should've been 6
Code:

 9 . 4 | . 3 . | . . 5
 7 . . | 2 . . | 6 . .
 . . . | . . 5 | . . .
-------+-------+------
 . . 3 | . . 1 | 9 . 6
 . 1 . | . 9 . | . 8 .
 5 . 9 | 7 . . | 3 . .
-------+-------+------
 . . . | 6 . . | . . .
 . . 2 | . . 8 | . . 7
 6 . . | . 1 . | 2 . 9

~ Pat
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arkietech



Joined: 31 Jul 2008
Posts: 1727
Location: Northwest Arkansas USA

PostPosted: Sun Jun 08, 2014 11:14 am    Post subject: Reply with quote

Pat wrote:
maybe r9c1 should've been 6


Very Happy Thanks Pat! Now it is a nice newspaper puzzle!
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