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daj95376
Joined: 23 Aug 2008
Posts: 3854
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 Posted: Mon Dec 14, 2009 6:43 pm Post subject: Puzzle XY 09/12/14 BBDB |
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| Code: | +-----------------------+
| . 5 . | . . 6 | . 1 8 |
| 4 . . | . . . | . . . |
| . . . | . . 1 | . 9 6 |
|-------+-------+-------|
| . . . | 6 . 8 | 1 . . |
| . . . | . 1 . | . . . |
| 8 . 5 | 2 . 3 | . 6 . |
|-------+-------+-------|
| . . . | 8 . . | . 7 1 |
| 7 . 6 | . . 2 | 9 3 . |
| 1 . 9 | . . . | 8 . . |
+-----------------------+
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Play this puzzle online at the Daily Sudoku site |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Tue Dec 15, 2009 12:53 am Post subject: |
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A fun BBDB Puzzle taking 11 steps including x-wings, finned x-wings, Remote Pairs, kites, w-wings, potential xy-wings with extended vertex and, of course, transports.
Ted |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Wed Dec 16, 2009 12:38 pm Post subject: |
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This puzzle has a shortcut to bypass three steps.
| Code: | r68 X-Wing <> 4 r1347c5,r459c9
<49+5> XY-Wing r7c6/r2c6+r8c5 <> 5 r3c5,r9c6
c67\r25 finned X-Wing <> 5 r2c8
r48\c59 finned X-Wing <> 5 r5c9
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| Code: | <59> UR r25c46
(3)r2c4 - (3=27)r13c5 - (7)r4c5
(7)r5c46 - (7)r4c5
+--------------------------------------------------------------+
| 9 5 237 | 347 237 6 | 34 1 8 |
| 4 6 1 | 59+3 8 59 | 35 2 7 |
| 23 237 8 | 45 237 1 | 45 9 6 |
|--------------------+--------------------+--------------------|
| 23 2379 237 | 6 9-7 8 | 1 4 5 |
| 6 479 47 | 59+7 1 59+7 | 2 8 3 |
| 8 1 5 | 2 4 3 | 7 6 9 |
|--------------------+--------------------+--------------------|
| 5 234 234 | 8 39 49 | 6 7 1 |
| 7 8 6 | 1 5 2 | 9 3 4 |
| 1 34 9 | 37 6 47 | 8 5 2 |
+--------------------------------------------------------------+
# 41 eliminations remain
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Otherwise, the <59> UR can be replaced with:
| Code: | <39+7> XY-Wing r7c5/r4c5+r9c4 <> 7 r5c4
r34\c25 finned X-Wing <> 7 r5c2 -or-
r3 b5 Empty Rectangle <> 7 r5c2
-4r5c3 7r5c3 7r9c6 4r9c2 [gM-Wing ] <> 4 r5c2,r7c3 -or-
-4r9c6 7r9c6 7r5c3 4r7c3 [gM-Wing ] <> 4 r7c6,r9c2
+--------------------------------------------------------------+
| 9 5 237 | 347 237 6 | 34 1 8 |
| 4 6 1 | 359 8 59 | 35 2 7 |
| 23 237 8 | 45 237 1 | 45 9 6 |
|--------------------+--------------------+--------------------|
| 23 2379 237 | 6 79 8 | 1 4 5 |
| 6 49 47 | 59 1 579 | 2 8 3 |
| 8 1 5 | 2 4 3 | 7 6 9 |
|--------------------+--------------------+--------------------|
| 5 234 234 | 8 39 49 | 6 7 1 |
| 7 8 6 | 1 5 2 | 9 3 4 |
| 1 34 9 | 37 6 47 | 8 5 2 |
+--------------------------------------------------------------+
# 39 eliminations remain
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Wed Dec 16, 2009 4:50 pm Post subject: |
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This lived up to its name. I used nine assorted steps and finished with two Hidden URs on the same UR and an XY-Chain. It's unusual for me with this many steps not to have found any ERs.
Danny, as to the shortcut to bypass three steps, that's fine. But in my personal solving, minimizing the number of steps is generally not a goal. With my scattershot approach I play whatever moves I see available. |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Wed Dec 16, 2009 7:40 pm Post subject: |
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| Marty R. wrote: | This lived up to its name. I used nine assorted steps and finished with two Hidden URs on the same UR and an XY-Chain. It's unusual for me with this many steps not to have found any ERs.
Danny, as to the shortcut to bypass three steps, that's fine. But in my personal solving, minimizing the number of steps is generally not a goal. With my scattershot approach I play whatever moves I see available. |
Yes, your point is well taken. My point was to show the presence of the UR elimination and that it was a benefit. In the latter case, I needed to show how many of my solver's steps it would save.
When I reviewed this puzzle, I knew it would need several steps. In fact, I almost discarded it for needing too many steps. Then I noticed that my solver had found a UR pattern with one extra candidate in three of the four cells. It also indicated there was only two extra candidate values in those three cells. This implied a UR pattern outside those my solver can handle ... but which I might have a chance solving manually.
| Code: | *** 1x bivalue cells: <59> UR r25c46 cand count = 4/2,3,3,3
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So, I tackled it and found an easy but useful elimination. Since everyone was having such success finding patterns in other puzzles that I'd posted recently, I decided to post this puzzle to see if anyone else caught the UR.
I fully admit that this puzzle is atypical of those I should be posting. Just like the BBDB+++ puzzle is an occasional exception.
Regards, Danny |
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