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dongrave
Joined: 06 Mar 2014
Posts: 572
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 Posted: Thu Nov 26, 2015 2:38 pm Post subject: Another 1sudolu.net Evil Puzzle |
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The only single step solution that I found for this is awful ugly! Could someone out there show me a 'nice' single-stepper?
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1sudoku.net #528902 Evil
+-------+-------+-------+
| 6 . . | . 9 . | . . 4 |
| 8 . . | 2 . 4 | . . 7 |
| . . 4 | . 6 . | 8 . . |
+-------+-------+-------+
| . 2 . | 1 . 8 | . 5 . |
| . . . | . . . | . . . |
| . 7 . | 3 . 5 | . 4 . |
+-------+-------+-------+
| . . 2 | . 5 . | 4 . . |
| 5 . . | 7 . 9 | . . 2 |
| 7 . . | . 1 . | . . 5 |
+-------+-------+-------+
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JC Van Hay
Joined: 13 Jun 2010
Posts: 494
Location: Charleroi, Belgium
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| Posted: Thu Nov 26, 2015 6:53 pm Post subject: |
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| To optimally solve the puzzle, I need Singles, 1 Locked Candidates, 1 Naked Pair and 2 "2-Fishes" or Singles, 2 Locked Candidates, 1 Naked Pair and 1 Kraken 9R9. Which do you prefer ? |
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dongrave
Joined: 06 Mar 2014
Posts: 572
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| Posted: Thu Nov 26, 2015 7:53 pm Post subject: |
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| JC Van Hay wrote: | | To optimally solve the puzzle, I need Singles, 1 Locked Candidates, 1 Naked Pair and 2 "2-Fishes" or Singles, 2 Locked Candidates, 1 Naked Pair and 1 Kraken 9R9. Which do you prefer ? |
Holy crow! No WONDER my solution is SO ugly! ugh. |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Fri Nov 27, 2015 3:37 am Post subject: |
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| Code: |
+------------+--------+---------------+
| 6 35 7 | 8 9 1 | 235 23 4 |
| 8 159 159 | 2 3 4 | 1569 169 7 |
| 2 139 4 | 5 6 7 | 8 139 139 |
+------------+--------+---------------+
| 34 2 69 | 1 47 8 | 379 5 369 |
| 34 158 158 | 9 47 6 | 1237 1238 138 |
| 19 7 68 | 3 2 5 | 19 4 68 |
+------------+--------+---------------+
| 19 189 2 | 6 5 3 | 4 7 189 |
| 5 4 13 | 7 8 9 | 136 136 2 |
| 7 6 389 | 4 1 2 | 39 389 5 |
+------------+--------+---------------+
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Play this puzzle online at the Daily Sudoku site
Just wanted to post basics. I can't make JC's Kraken work. There's a Skyscraper on 8. There are some UR and DP possibilities, including a 34-47-37 in r5 but so far I haven't been able to do anything with them. I also haven't found JC's fish yet, |
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dongrave
Joined: 06 Mar 2014
Posts: 572
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| Posted: Fri Nov 27, 2015 6:00 am Post subject: |
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| Marty R. wrote: |
Just wanted to post basics. I can't make JC's Kraken work. There's a Skyscraper on 8. There are some UR and DP possibilities, including a 34-47-37 in r5 but so far I haven't been able to do anything with them. I also haven't found JC's fish yet, |
Thanks Marty! That looks familiar alright! You know what? If I ever publish my book, I'm going to use the pen name 'JC Kraken'! Here's my one-stepper that I told you about (pretty darn ugly, isn't it?)
(8=6)r6c3-(6=9)r4c3-(9=1)r6c1[-(1=9)r7c1-r7c9;-(1=9)r6c7-(9=3)r9c7-(3=16)r8c78]-(19=8)r7c9-(8=6)r6c9 => ugh. |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Fri Nov 27, 2015 12:51 pm Post subject: |
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| Quote: | | (8=6)r6c3-(6=9)r4c3-(9=1)r6c1[-(1=9)r7c1-r7c9;-(1=9)r6c7-(9=3)r9c7-(3=16)r8c78]-(19=8)r7c9-(8=6)r6c9 => ugh.. |
Don, you're getting the hang of it. As much as I hate to rain on your parade, I'm gonna do it anyways.
1) In the red area not all the inferences alternate. There are two consecutive weak inferences; the 2nd dash needs to be an =.
2) The end is in cyan. If the intent here was a pincer attack, the notation should end with =8, so as to eliminate something. I've taken the liberty of rewriting.
(8=6)r6c3-(6=9)r4c3-(9=1)r6c1[-(1=9)r7c1-(9=18)r7c9=> -8r6c9,although I don't know how far the elimination take us. |
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JC Van Hay
Joined: 13 Jun 2010
Posts: 494
Location: Charleroi, Belgium
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| Posted: Fri Nov 27, 2015 1:18 pm Post subject: |
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Marty : after the Skyscraper on 8s, there is a Skyscraper on 9s.
dongrave : I have the same single step  : 8r6c9 -> 9R9={}. Here is a less ugly interpretation using only 5 constraints :
r9c8=9 -> r7c9=8, r6c9=6
or
Skyscraper(9r6c17, 9r9c37) -> r4c3=6, r6c8=8, r6c9=6
Or using your notation :
(8=6)r6c3-(6=9)r4c3-[9r6c1=9r6c8-9r9c7; 9r9c3]=(9-8)r9c8=8r7c9 :=> -8r6c9 |
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dongrave
Joined: 06 Mar 2014
Posts: 572
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| Posted: Fri Nov 27, 2015 1:29 pm Post subject: |
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| Marty R. wrote: | | Don, you're getting the hang of it. As much as I hate to rain on your parade, I'm gonna do it anyways. |
Hi Marty, Thanks! You didn't rain on my parade, I appreciate your help! I see that I screwed up a few things with my ugly expression. I intended to use the square brackets (even though it's obviously not right) to have two sub-expressions that both begin after the strong link '(9=1)r6c1' (which is why they both begin with a weak link) and have the 1st sub-expression end by showing you that 'r7c9<>9' and then have the 2nd one end by showing you that 'r8c78=16' so 'r7c9<>1' so r7c9=8 so r6c9=6 and then I forgot to put 'contradiction' (because r6c3 and c9 are both 6) and then I also didn't put the conclusion '=> r6c3<>6' (at least I remembered to put the 'ugh' at the end). How the heck do you represent what I was trying to do in Eureka? I thought I had it (darn). Oh! one last thing - when I look for single step chains, I always make sure that the conclusion solves it so at least that part I got right! (I think)  Thanks again! |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Fri Nov 27, 2015 3:57 pm Post subject: |
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| Quote: | | Code: | +------------+--------+---------------+
| 6 35 7 | 8 9 1 | 235 23 4 |
| 8 159 159 | 2 3 4 | 1569 169 7 |
| 2 139 4 | 5 6 7 | 8 139 139 |
+------------+--------+---------------+
| 34 2 69 | 1 47 8 | 379 5 369 |
| 34 158 158 | 9 47 6 | 1237 1238 138 |
| 19 7 68 | 3 2 5 | 19 4 68 |
+------------+--------+---------------+
| 19 189 2 | 6 5 3 | 4 7 189 |
| 5 4 13 | 7 8 9 | 136 136 2 |
| 7 6 389 | 4 1 2 | 39 389 5 |
+------------+--------+---------------+ |
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Don, this is my best shot at achieving your desired result:
(8=6)r6c3-(6=9)r4c3-r4c79=r6c7-(9=3)r9c7-(3=16)r8c78-(1=98)r7c9=> -8r6c9.
The (3=16) might be clearer to the reader as (36=1), but I write ALS's the way that the experts like them.
If we want to use r7c1 we could use the following from the 3rd term through the end.
(9=1)r6c1-(1=9)r7c1-(9=18)r7c9=> -8r6c9
Last edited by Marty R. on Fri Nov 27, 2015 4:02 pm; edited 1 time in total |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Fri Nov 27, 2015 3:57 pm Post subject: |
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Not a single-stepper, but not so bad.
In Marty's after basics grid there is an extended XY-wing that take out 3 in R8C78, revealing a 16 pair.
After a few more basics there is a W-wing 89 - 68 that takes out 9 in R7C1.
Keith |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Fri Nov 27, 2015 4:09 pm Post subject: |
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| Keith, I'm afraid that I don't know what an extended XY-Wing is and I can't find anything that looks wingy with pincer 3. |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Fri Nov 27, 2015 4:51 pm Post subject: |
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| Marty R. wrote: | | Keith, I'm afraid that I don't know what an extended XY-Wing is and I can't find anything that looks wingy with pincer 3. |
Marty,
Maybe you call it "transport". Look at 13 - 19 - 19 - 19 - 39 which has pincers on 3.
Keith |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Fri Nov 27, 2015 6:18 pm Post subject: |
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Keith,until recently I looked for those all the time and don't know why I stopped.. I call it an XY-Wing Chain because that's what it was called on the site where I learned it.
(I see your Lions are on a roll with four W's in the last six including some division rivals.) |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Fri Nov 27, 2015 6:41 pm Post subject: |
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Marty,
Helmut and I were discussing the other day these "useless" XY-wings where you can extend the pincers with a couple of coloring links. They can be quite handy, but you need to remember to look for them.
I like that this puzzle succumbs to this and a classic W-wing.
Even better than the Lions is the fact that U. of Michigan once again has a football team.
Keith |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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dongrave
Joined: 06 Mar 2014
Posts: 572
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| Posted: Fri Nov 27, 2015 7:16 pm Post subject: |
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| keith wrote: | ... dongrave, you may want to read it as a compendium of tips for pencil and paper solvers.
Keith |
Thanks Keith! I'll do that! And thanks to Marty and Van Hay for your help! Don. |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Fri Nov 27, 2015 8:51 pm Post subject: |
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| Quote: | | Helmut and I were discussing the other day these "useless" XY-wings where you can extend the pincers with a couple of coloring links. They can be quite handy, but you need to remember to look for them. |
I view pincer transport as one of the most powerful tools in the box. |
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