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Clement
Joined: 24 Apr 2006
Posts: 1111
Location: Dar es Salaam Tanzania
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 Posted: Sun Jul 24, 2016 6:39 am Post subject: Jul 24 VH |
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dongrave
Joined: 06 Mar 2014
Posts: 568
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| Posted: Sun Jul 24, 2016 2:35 pm Post subject: |
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This is the most surprising example yet of an incorrectly graded VH! Apparently Sam's bug is worse than Hugh and I suspected because in previous examples, it used an X-Wing when locked candidates would have sufficed. Here, I only saw one place that it could have incorrectly used an X-Wing and that was when a naked pair or a naked triple could have been used. Here's the position that I reached after very basic cross hatching (i.e. singles only).
| Code: |
+---------------+---------------+--------------+
| 5 3 4 | 9 7 8 | 6 1 2 |
| 127 8 179 | 23 234 6 | 34 5 479 |
| 267 69 79 | 5 234 1 | 348 39 4789 |
+---------------+---------------+--------------+
| 8 1 5 | 23 9 23 | 7 4 6 |
| 3 7 2 | 16 16 4 | 9 8 5 |
| 9 4 6 | 8 5 7 | 1 2 3 |
+---------------+---------------+--------------+
| 167 569 13789 | 4 1236 235 | 2358 39 189 |
| 14 2 1389 | 7 13 35 | 3458 6 1489 |
| 146 56 13 | 1236 8 9 | 2345 7 14 |
+---------------+---------------+--------------+
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I noticed at this point that it was possible to use the X-Wing on 9's in columns 2 and 8 instead of applying the naked 23 in column 4 or the naked 234 in row 2. Since Sam's bug is worse than we thought - and since Sam's obviously never going to fix it (because he's a bum), I would propose always naming the 'Subject' of incorrectly graded VHs to indicate that it's not really a VH (e.g. 'Jul 24 VH?', 'Jul 24 not VH'). That way people will know before going in to read the post. I don't like to open the solutions to VHs until I've solved them because I don't want to accidentally see the solution. Let me know what you think. Thanks, Don.
Last edited by dongrave on Sun Jul 24, 2016 8:34 pm; edited 3 times in total |
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richfa
Joined: 14 Feb 2016
Posts: 12
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| Posted: Sun Jul 24, 2016 3:15 pm Post subject: Did not think this was VH at all. |
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| I, too, only used simple methods throughout the entire puzzle! |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Mon Jul 25, 2016 12:34 am Post subject: |
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| Quote: | | I would propose always naming the 'Subject' of incorrectly graded VHs to indicate that it's not really a VH (e.g. 'Jul 24 VH?', 'Jul 24 not VH'). That way people will know before going in to read the post. I don't like to open the solutions to VHs until I've solved them because I don't want to accidentally see the solution. Let me know what you think. Thanks, Don. |
Don, I'm my usual dense self today and I don't understand what that change in the subject line does to help prevent accidentally seeing the solution. Isn't the secret to preventing accidental viewings never opening the thread until you've completed the puzzle? |
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dongrave
Joined: 06 Mar 2014
Posts: 568
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| Posted: Mon Jul 25, 2016 1:27 am Post subject: |
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| You're not dense Marty! I just didn't explain it very well. The reasoning behind my suggestion goes as follows. I've just solved what is rated a VH puzzle - but I solved it without using any VH moves. Now my problem is that I don't know if I screwed up and the puzzle actually does require a VH move - or whether the puzzle's rating is wrong and it didn't require a VH move. I don't want to click on the subject line that lists the date and the rating of VH because I don't want to accidentally see the solution if the rating is correct - but I don't want to waste my time redoing the puzzle only to discover that its rating was wrong. I should have explained it a little better. I didn't make myself clear in my original posting. Thanks, Don. |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Mon Jul 25, 2016 3:11 am Post subject: |
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| Don, I had a grid very similar to the one you posted. The puzzle solved with an X-Wing. Only a minority of the VHs use an X-Wing and I thought I might've screwed up the basics and couldn't find the solution. So I ran the automated basics on Helmut's site and was quite surprised to see "congratulations you've solved the puzzle." I'd strongly recommend you or anyone else do the same whenever you have doubts about your basics. |
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hughwill
Joined: 05 Apr 2010
Posts: 424
Location: Birmingham UK
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| Posted: Mon Jul 25, 2016 10:43 am Post subject: |
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| dongrave wrote: | | Since Sam's bug is worse than we thought - and since Sam's obviously never going to fix it (because he's a bum), |
Maybe best not to diss him- he's got other fish to fry but he allows the site
to continue despite clearly and understandably losing interest. He did fix
some annoying bugs a couple of years ago. Given the time it's been around
the site has not done badly and I can forgive its quirks - in fact the non-VH
VH is quite interesting in that it's fun to try working out what the bug is....as
you have done.
What you can do is to go to the point just before it changes from VH to
Easy/Medium/Hard on the Grade button:
| Code: |
+--------------+------------+-------------+
| 5 3 4 | 9 7 8 | 6 1 2 |
| 127 8 179 | 23 234 6 | 34 5 479 |
| 267 69 79 | 5 234 1 | 348 39 4789 |
+--------------+------------+-------------+
| 8 1 5 | 23 9 23 | 7 4 6 |
| 3 7 2 | 16 16 4 | 9 8 5 |
| 9 4 6 | 8 5 7 | 1 2 3 |
+--------------+------------+-------------+
| 167 69 13789 | 4 1236 23 | 5 39 189 |
| 14 2 89 | 7 13 5 | 348 6 1489 |
| 146 5 3 | 16 8 9 | 2 7 14 |
+--------------+------------+-------------+
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Play this puzzle online at the Daily Sudoku site
and then press Hint. This might go over some already solved steps before
giving one that it says it can't explain. That's the one it thinks makes it VH.
In this case it is the X-Wing that it uses to setting r3c3 to 7.
Hugh |
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bat999
Joined: 09 Jul 2015
Posts: 55
Location: UK
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| Posted: Mon Jul 25, 2016 7:05 pm Post subject: |
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| dongrave wrote: | | ... Sam's bug is worse than we thought - and since Sam's obviously never going to fix it... |
Hi
The puzzles at http://forum.enjoysudoku.com/ are good quality.
I think they are mostly provided by the same daj who used to post puzzles here at dailysudoku.com. |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Mon Jul 25, 2016 8:50 pm Post subject: |
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Hi Bat,
What makes you think DAJ, aka Danny A. Jones? I don't see it, unless he's feeding puzzles to Dan. By the way, we don't even know if he's alive, as he hasn't posted in a year and no one knows anything. |
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dongrave
Joined: 06 Mar 2014
Posts: 568
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| Posted: Mon Jul 25, 2016 9:54 pm Post subject: |
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Hi Marty, What's Helmut's site that you referred to? I'll check it out!
You're right Hugh. I shouldn't be such an ingrate! I do get a lot of enjoyment from this site - flaws and all! |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Mon Jul 25, 2016 11:56 pm Post subject: |
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Don, this is a link to the page on Helmut's site where a puzzle is imported. If you run into any problems, just ask. By the way, Helmut was active here for years, posting under the user name nataraj.
http://sudoku.saueregger.at/HSH/HSF.htm |
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dongrave
Joined: 06 Mar 2014
Posts: 568
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| Posted: Tue Jul 26, 2016 10:11 pm Post subject: |
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| Thanks Marty, I'll check it out! Hey! I remember seeing that name when I was reading old posts trying to learn Eureka. |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Mon Aug 01, 2016 11:06 am Post subject: |
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Danny Jones is a computer programmer, retired from Lawrence Livermore National Labs. A tipoff is that he used his zip code in his user name. There are many of his puzzles archived on this site.
Nataraj is Helmut Saueregger, who lives near Vienna, Austria. His site is quite cool, once you get the hang of it. Also, his puzzles are quite good. Please follow the link here:
| keith wrote: | All,
I am concerned that the DS discussion (where you are now) and even the Daily Sudoku site itself may disappear without warning. The site owner, Sam Griffiths-Jones, has been AWOL for many years.
To that end, the discussion can continue at Jason Lion's site, New Sudoku Players' Forum. Also, Helmut Saueregger (Nataraj) has updated his formatter and helper at Sudok-o-Rama to meet the needs (as I understand them) of the way that many people use DS Draw/Play.
Please visit and bookmark the following link:
http://forum.enjoysudoku.com/post247644.html#p247644
I am not soliciting anyone to leave the Daily Sudoku site. It's just that if the site does disappear, how would you then know where to go? Please bookmark the link now. It will not be findable when or if you really need it, if the DS discussion forum disappears.
Many thanks to Helmut Saueregger at Sudok-o-Rama and Jason Lion at the New Sudoku Players' Forum for accommodating my concerns.
Keith |
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