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arkietech
Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA
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 Posted: Wed Jul 18, 2012 4:58 am Post subject: Menneske 2652767 |
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| 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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Play/Print online |
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TNova
Joined: 17 Jul 2012
Posts: 16
Location: Bromley, UK
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| Posted: Wed Jul 18, 2012 3:37 pm Post subject: |
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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: 5770
Location: Rochester, NY, USA
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TNova
Joined: 17 Jul 2012
Posts: 16
Location: Bromley, UK
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| Posted: Wed Jul 18, 2012 4:22 pm Post subject: |
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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: 1834
Location: Northwest Arkansas USA
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| Posted: Wed Jul 18, 2012 4:24 pm Post subject: |
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| 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. 
| 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: 5770
Location: Rochester, NY, USA
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| Posted: Wed Jul 18, 2012 5:09 pm Post subject: |
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| 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: 2468
Location: Northern California Foothills
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| Posted: Wed Jul 18, 2012 5:49 pm Post subject: |
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6-cell Type 1 UR(57)r789c158; r8c8=6
Ted |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Wed Jul 18, 2012 5:58 pm Post subject: |
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| tlanglet wrote: | 6-cell Type 1 UR(57)r789c158; r8c8=6
Ted |
I guess I blew that one, thinking it needed another step.  |
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Luke451
Joined: 20 Apr 2008
Posts: 310
Location: Southern Northern California
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| Posted: Wed Jul 18, 2012 6:52 pm Post subject: |
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| 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: 1834
Location: Northwest Arkansas USA
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| Posted: Wed Jul 18, 2012 7:09 pm Post subject: |
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| tlanglet wrote: | | 6-cell Type 1 UR(57)r789c158; r8c8=6 |
Nice one Ted  |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Wed Jul 18, 2012 10:38 pm Post subject: |
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| Luke451 wrote: |
BUG-Lite, Ted!
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Luke,
Yes I remember, but I have never heard of a Type 1 BUG-Lite.
I really dislike naming patterns................ 
Ted |
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Luke451
Joined: 20 Apr 2008
Posts: 310
Location: Southern Northern California
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| Posted: Thu Jul 19, 2012 11:56 pm Post subject: |
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| tlanglet wrote: | | Luke451 wrote: |
BUG-Lite, Ted!
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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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