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keith
Joined: 19 Sep 2005 Posts: 3355 Location: near Detroit, Michigan, USA
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Posted: Sat Aug 16, 2014 2:22 pm Post subject: Free Press August 15, 2014 |
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Basics are hard!
Code: | Puzzle: FP081514
+-------+-------+-------+
| 1 . 4 | . . . | 8 . . |
| . 8 . | 4 . . | . . 3 |
| . . . | . . 2 | . . 4 |
+-------+-------+-------+
| . . . | . . 5 | . 7 9 |
| . . 3 | . . 7 | 1 . . |
| 7 1 . | 8 . . | . . . |
+-------+-------+-------+
| 4 6 . | 5 . . | . . . |
| 3 . . | . . 9 | . 4 . |
| . . 5 | . . . | 3 . 2 |
+-------+-------+-------+
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Play this puzzle online at the Daily Sudoku site
Keith |
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Marty R.
Joined: 12 Feb 2006 Posts: 5770 Location: Rochester, NY, USA
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Posted: Sat Aug 16, 2014 4:23 pm Post subject: |
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Code: |
+-----------------+-----------------+---------------+
| 1 23579 4 | 3679 35679 36 | 8 259 67 |
| 2569 8 2679 | 4 15679 16 | 2679 1259 3 |
| 569 3579 679 | 13679 8 2 | 679 159 4 |
+-----------------+-----------------+---------------+
| 268 24 268 | 13 13 5 | 246 7 9 |
| 2569 2459 3 | 269 2469 7 | 1 28 68 |
| 7 1 269 | 8 2469 46 | 246 3 5 |
+-----------------+-----------------+---------------+
| 4 6 128 | 5 23 38 | 79 89 178 |
| 3 27 18 | 267 267 9 | 5 4 18 |
| 89 79 5 | 17 147 148 | 3 6 2 |
+-----------------+-----------------+---------------+
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Play this puzzle online at the Daily Sudoku site
On puzzles like this I populate the grid via Draw/Play which greatly minimizes the chance of a mechanical error.
Type 3 UR (18), r78,c39
2r7c3=7r7c9-(7=6)r1c9-(6=8)r5c9-(8=2)r5c8-r5c45=r6c5=>r7c5<>2 |
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keith
Joined: 19 Sep 2005 Posts: 3355 Location: near Detroit, Michigan, USA
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Posted: Sat Aug 16, 2014 7:57 pm Post subject: |
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There is a slightly simpler chain in R17 that takes out 7 in R7C9 to solve the puzzle. The UR is still needed.
Pincers on 7: 67 36 38 89 79.
Keith |
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Marty R.
Joined: 12 Feb 2006 Posts: 5770 Location: Rochester, NY, USA
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Posted: Sat Aug 16, 2014 8:11 pm Post subject: |
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keith wrote: | There is a slightly simpler chain in R17 that takes out 7 in R7C9 to solve the puzzle. The UR is still needed.
Pincers on 7: 67 36 38 89 79.
Keith |
Keith,
I don't understand. The first sentence says the chain solves it and the second says the UR is still needed. |
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keith
Joined: 19 Sep 2005 Posts: 3355 Location: near Detroit, Michigan, USA
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Posted: Sat Aug 16, 2014 8:15 pm Post subject: |
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Marty R. wrote: | keith wrote: | There is a slightly simpler chain in R17 that takes out 7 in R7C9 to solve the puzzle. The UR is still needed.
Pincers on 7: 67 36 38 89 79.
Keith |
Keith,
I don't understand. The first sentence says the chain solves it and the second says the UR is still needed. |
Marty, this chain is proposed as an alternative to yours, after the UR is played. However, my chain is also available before the UR, which is then still needed.
Take the steps (chain, UR) in any order. And yes, the 18 UR eliminations are slightly different, depending on the order, but the end result is the same.
Keith |
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Marty R.
Joined: 12 Feb 2006 Posts: 5770 Location: Rochester, NY, USA
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Posted: Sat Aug 16, 2014 10:51 pm Post subject: |
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Quote: | Marty, this chain is proposed as an alternative to yours, after the UR is played. |
Maybe I'm having a day full of senior moments, but after the UR is played (at least the way I played it) the puzzle is solved and there's no need for a chain or anything else after the UR. |
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keith
Joined: 19 Sep 2005 Posts: 3355 Location: near Detroit, Michigan, USA
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Posted: Sun Aug 17, 2014 2:09 am Post subject: |
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Marty R. wrote: | Code: |
+-----------------+-----------------+---------------+
| 1 23579 4 | 3679 35679 36 | 8 259 67 |
| 2569 8 2679 | 4 15679 16 | 2679 1259 3 |
| 569 3579 679 | 13679 8 2 | 679 159 4 |
+-----------------+-----------------+---------------+
| 268 24 268 | 13 13 5 | 246 7 9 |
| 2569 2459 3 | 269 2469 7 | 1 28 68 |
| 7 1 269 | 8 2469 46 | 246 3 5 |
+-----------------+-----------------+---------------+
| 4 6 128 | 5 23 38 | 79 89 178 |
| 3 27 18 | 267 267 9 | 5 4 18 |
| 89 79 5 | 17 147 148 | 3 6 2 |
+-----------------+-----------------+---------------+
|
Play this puzzle online at the Daily Sudoku site
On puzzles like this I populate the grid via Draw/Play which greatly minimizes the chance of a mechanical error.
Type 3 UR (18), r78,c39
2r7c3=7r7c9-(7=6)r1c9-(6=8)r5c9-(8=2)r5c8-r5c45=r6c5=>r7c5<>2 |
Maybe I'm having a senior moment, but I think Marty published a solution with a UR and then a chain?
Keith |
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Marty R.
Joined: 12 Feb 2006 Posts: 5770 Location: Rochester, NY, USA
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Posted: Sun Aug 17, 2014 3:53 am Post subject: |
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keith wrote: | Marty R. wrote: | Code: |
+-----------------+-----------------+---------------+
| 1 23579 4 | 3679 35679 36 | 8 259 67 |
| 2569 8 2679 | 4 15679 16 | 2679 1259 3 |
| 569 3579 679 | 13679 8 2 | 679 159 4 |
+-----------------+-----------------+---------------+
| 268 24 268 | 13 13 5 | 246 7 9 |
| 2569 2459 3 | 269 2469 7 | 1 28 68 |
| 7 1 269 | 8 2469 46 | 246 3 5 |
+-----------------+-----------------+---------------+
| 4 6 128 | 5 23 38 | 79 89 178 |
| 3 27 18 | 267 267 9 | 5 4 18 |
| 89 79 5 | 17 147 148 | 3 6 2 |
+-----------------+-----------------+---------------+
|
Play this puzzle online at the Daily Sudoku site
On puzzles like this I populate the grid via Draw/Play which greatly minimizes the chance of a mechanical error.
Type 3 UR (18), r78,c39
2r7c3=7r7c9-(7=6)r1c9-(6=8)r5c9-(8=2)r5c8-r5c45=r6c5=>r7c5<>2 |
Maybe I'm having a senior moment, but I think Marty published a solution with a UR and then a chain?
Keith |
Keith,
We haven't been on the same wave length. My solution was a one-step chain. But the UR was the basis for the chain. It was a Type 3 and to kill the DP either r7c3=2 or r7c9=7. Thus the UR gave me the premise for the chain. I did nothing with the UR other than to use the extra candidates as the potential pincers, the equivalent of (2=7) as the starting point of the chain.
Hope that clears things up.
Marty |
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dongrave
Joined: 06 Mar 2014 Posts: 568
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Posted: Sun Aug 17, 2014 2:45 pm Post subject: |
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Hi Marty, NOW I see what you're talking about! Just like Keith, I thought that your solution consisted of two steps (the UR followed by the chain). It wasn't until I saw your last post that I realized that you were performing the chain without first executing the UR. I probably should have realized it since your solution began '2r7c3=7r7c9...' instead of '(2=1)r7c3-(1=7)r7c9...' but I'm still learning Eureka notation. To avoid this kind of confusion, is it possible to include that fact that you're applying the UR during the steps of the chain within the Eureka expression? For instance, something like '2r7c3=(7r7c9=UR:18r78c39)-(7=6)r1c9...' or is that not the standard convention? Thanks, Don. |
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Marty R.
Joined: 12 Feb 2006 Posts: 5770 Location: Rochester, NY, USA
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Posted: Sun Aug 17, 2014 3:29 pm Post subject: |
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Don, some people do embed UR information within the notation. I'm not crazy about it. I'm sorry that it was confusing. I wonder if it would've been clearer if I did it all on one line, like below.
Type 3 UR (18), r78,c39: 2r7c3=7r7c9-(7=6)r1c9-(6=8)r5c9-(8=2)r5c8-r5c45=r6c5=>r7c5<>2 |
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keith
Joined: 19 Sep 2005 Posts: 3355 Location: near Detroit, Michigan, USA
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Posted: Sun Aug 17, 2014 4:36 pm Post subject: |
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Marty,
I saw the (your) UR as a Type 4 that then opens up the chain as a second step.
Eureka is not my strong point, I just follow the cells and not the link xx.
Maybe the Gods of Eureka can figure out a neater way to denote the pseudocells that can arise in URs (and other "almost" patterns).
Keith |
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Clement
Joined: 24 Apr 2006 Posts: 1111 Location: Dar es Salaam Tanzania
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Posted: Sun Aug 17, 2014 11:08 pm Post subject: Free Press August 15, 2014 |
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Code: |
+----------------+-----------------+---------------+
| 1 2359 4 | 3679 35679 h36 | 8 259 67 |
| 2569 8 2679 | 4 15679 16 | 2679 1259 3 |
| 569 3579 679 | 13679 8 2 | 679 159 4 |
+----------------+-----------------+---------------+
| 268 d24 268 | 13 13 5 | e246 7 9 |
| 2569 2459 3 | 269 2469 7 | 1 28 68 |
| 7 1 269 | 8 2469 g46 | f246 3 5 |
+----------------+-----------------+---------------+
| 4 6 b128 | 5 a23 8-3 | 79 89 178 |
| 3 c27 18 | 267 267 9 | 5 4 18 |
| 89 79 5 | 17 147 148 | 3 6 2 |
+----------------+-----------------+---------------+
| (3=2)r7c5-r7c3=r8c2-(2=4)r4c2-r4c7=r6c7-(4=6)r6c6-(6=3)r1c6 => -3r7c6; stte. |
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