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Menneske 2652767

 
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arkietech



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

PostPosted: Wed Jul 18, 2012 4:58 am    Post subject: Menneske 2652767 Reply with quote

Code:

 *-----------*
 |..3|.8.|...|
 |.8.|...|...|
 |...|.4.|3.1|
 |---+---+---|
 |6.4|...|.2.|
 |3..|7..|...|
 |.57|.3.|.4.|
 |---+---+---|
 |...|.2.|9..|
 |.2.|9.3|1..|
 |..9|..1|4..|
 *-----------*
 

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TNova



Joined: 17 Jul 2012
Posts: 16
Location: Bromley, UK

PostPosted: Wed Jul 18, 2012 3:37 pm    Post subject: Reply with quote

Greetings. This is my first post on here, and I only registered on the site yesterday. I used to do Sudokus a lot many years ago when I commuted by train to work, but then I stopped for many years. But now retired I've decided to dive back in again about a month ago to keep my brain cells active, and it's not quite plain sailing.

First of all, many thanks to Arkietech and others for posting these additional puzzles which are actually much more interesting than the site's own ones.

But this one especially. I reached the situation below,where I had a long delay.

Code:
+---------+-----------+-----------+
| 1  4 3  | 26 8  579 | 25 79  67 |
| 29 8 56 | 3  1  579 | 25 679 4  |
| 29 7 56 | 26 4  59  | 3  8   1  |
+---------+-----------+-----------+
| 6  1 4  | 5  9  8   | 7  2   3  |
| 3  9 2  | 7  6  4   | 8  1   5  |
| 8  5 7  | 1  3  2   | 6  4   9  |
+---------+-----------+-----------+
| 57 3 1  | 4  2  6   | 9  57  8  |
| 4  2 8  | 9  57 3   | 1  567 67 |
| 57 6 9  | 8  57 1   | 4  3   2  |
+---------+-----------+-----------+


But I solved the puzzle when I realised that if R3C4 was 2, this then forced R2C1 to be 2 and (using all the cells in R3) R2c3 to be 5. That didn't leave a valid value for R2C7, so R3C6 had to be 6 and that solved the puzzle.

But I'm trying to get my head around some of these solving techniques that have evolved during my absence, so I was curious to see if my HodoKu program would solve the puzzle in the same way I did. So I reloaded the situation, and it ignored my method and decided there was a hidden rectangle with the 7's and 9's in R1&2 and C6&8 so the 9 in R2C6 could be eliminated.

Annoyingly I'd seen the 7's and 9's in these four cells but given up thinking that there were too many extra 7's and 9's elsewhere. I still don't really know it works - the Hodoku documentation only gives simpler examples than this one. I'd love to add this extra technique to my solving repertoire.

At least I solved the puzzle without using any hints - unlike the July 7 AU tough posted on here which I think is the hardest puzzle I've tried since my resumption.

Tim
(ps - how can I change the font to to a fixed width one, so that I can make the grid line up properly like everyone else's? I can only see how to change the font size and colour.).
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Marty R.



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

PostPosted: Wed Jul 18, 2012 3:54 pm    Post subject: Reply with quote

TNova,

I edited your post to add the Code tags. They create a fixed-width font.

Welcome to the forum.

Marty

P.S. You might also check out this post.

http://www.dailysudoku.co.uk/sudoku/forums/viewtopic.php?t=1905
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TNova



Joined: 17 Jul 2012
Posts: 16
Location: Bromley, UK

PostPosted: Wed Jul 18, 2012 4:22 pm    Post subject: Reply with quote

Marty, many thanks. I've read the post you referred to, so issue solved.

In the paragraph beneath the grid, "R3C6" should read "R3C4".

TNova
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arkietech



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

PostPosted: Wed Jul 18, 2012 4:24 pm    Post subject: Reply with quote

TNova wrote:
I was curious to see if my HodoKu program would solve the puzzle in the same way I did. So I reloaded the situation, and it ignored my method and decided there was a hidden rectangle with the 7's and 9's in R1&2 and C6&8 so the 9 in R2C6 could be eliminated.

Annoyingly I'd seen the 7's and 9's in these four cells but given up thinking that there were too many extra 7's and 9's elsewhere. I still don't really know it works - the Hodoku documentation only gives simpler examples than this one. I'd love to add this extra technique to my solving repertoire.


Tim,I used cells in r2,3 connected in b1 to get the result you were looking for. It is an AIC (chain) that uses almost locked sets (ALS) and a structure similar to an xy-wing (3sis) 3 equal signs in the notation.

Hope this helps. I am learning also ... very slowly. Very Happy
Code:
 *--------------------------------------------------*
 | 1    4    3    | 26   8    579  | 25   679  67   |
 |a29   8   b56   | 3    1    57-9 |b25   679  4    |
 | 2-9  7   c56   | 26   4   c59   | 3    8    1    |
 |----------------+----------------+----------------|
 | 6    1    4    | 5    9    8    | 7    2    3    |
 | 3    9    2    | 7    6    4    | 8    1    5    |
 | 8    5    7    | 1    3    2    | 6    4    9    |
 |----------------+----------------+----------------|
 | 57   3    1    | 4    2    6    | 9    57   8    |
 | 4    2    8    | 9    57   3    | 1    567  67   |
 | 57   6    9    | 8    57   1    | 4    3    2    |
 *--------------------------------------------------*
(9=2)r2c1-(2=56)r2c37-(6=59)r3c36 => -9r2c6,r3c1; stte

if r2c1 is not a 9 then r3c6 is a 9
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Marty R.



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

PostPosted: Wed Jul 18, 2012 5:09 pm    Post subject: Reply with quote

Code:
 *---------------------------------------------------*
 | 1    4    3    |  26   8    579  | 25   679  67   |
 |C29   8   E56   |  3    1    579  |D25   679  4    |
 |B29  7     5-6  | A26   4    59   | 3    8    1    |
 |----------------+----------------------------------|
 | 6    1    4    |  5    9    8    | 7    2    3    |
 | 3    9    2    |  7    6    4    | 8    1    5    |
 | 8    5    7    |  1    3    2    | 6    4    9    |
 |----------------+----------------------------------|
 | 57   3    1    |  4    2    6    | 9    57   8    |
 | 4    2    8    |  9    57   3    | 1    567  67   |
 | 57   6    9    |  8    57   1    | 4    3    2    |
 *---------------------------------------------------*


ABCDE. R3c4=2--->r2c3=6; r3c3<>6.

A two-step solution is r8c8=6 to break up the 57 DP, which turns the 79 DP in boxes 23 into a Type 2 UR; r3c6<>5.
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tlanglet



Joined: 17 Oct 2007
Posts: 2461
Location: Northern California Foothills

PostPosted: Wed Jul 18, 2012 5:49 pm    Post subject: Reply with quote

6-cell Type 1 UR(57)r789c158; r8c8=6

Ted
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Marty R.



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

PostPosted: Wed Jul 18, 2012 5:58 pm    Post subject: Reply with quote

tlanglet wrote:
6-cell Type 1 UR(57)r789c158; r8c8=6

Ted


I guess I blew that one, thinking it needed another step. Embarassed
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Luke451



Joined: 20 Apr 2008
Posts: 310
Location: Southern Northern California

PostPosted: Wed Jul 18, 2012 6:52 pm    Post subject: Reply with quote

tlanglet wrote:
6-cell Type 1 UR(57)r789c158; r8c8=6

Ted

BUG-Lite, Ted!

...and a warm welcome to TNova.
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arkietech



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

PostPosted: Wed Jul 18, 2012 7:09 pm    Post subject: Reply with quote

tlanglet wrote:
6-cell Type 1 UR(57)r789c158; r8c8=6


Nice one Ted Exclamation Very Happy
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tlanglet



Joined: 17 Oct 2007
Posts: 2461
Location: Northern California Foothills

PostPosted: Wed Jul 18, 2012 10:38 pm    Post subject: Reply with quote

Luke451 wrote:

BUG-Lite, Ted!


Luke,
Yes I remember, but I have never heard of a Type 1 BUG-Lite.

I really dislike naming patterns................ Confused

Ted
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Luke451



Joined: 20 Apr 2008
Posts: 310
Location: Southern Northern California

PostPosted: Thu Jul 19, 2012 11:56 pm    Post subject: Reply with quote

tlanglet wrote:
Luke451 wrote:

BUG-Lite, Ted!

Luke,
Yes I remember, but I have never heard of a Type 1 BUG-Lite.



Rightly or not, I have been known to champion the Type 1 DP lost cause. Here's an example in a thread that also contains a link to a "Type 1 MUG."
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