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daj95376
Joined: 23 Aug 2008
Posts: 3854
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 Posted: Sat Feb 19, 2011 11:40 pm Post subject: Puzzle 11/02/19 Difficult BBDB |
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| Code: | +-----------------------+
| 8 . . | . . 5 | . . 6 |
| . 5 . | 6 . 3 | . . . |
| . . . | 8 2 . | . . 1 |
|-------+-------+-------|
| . 4 5 | 9 . . | . 8 2 |
| . . 8 | . . 1 | 9 6 . |
| 6 9 . | . 8 . | . 4 7 |
|-------+-------+-------|
| . . . | . 1 . | 5 . . |
| . . . | 2 5 4 | . . . |
| 5 . 7 | 3 . 8 | . . . |
+-----------------------+
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Play this puzzle online at the Daily Sudoku site |
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Asellus
Joined: 05 Jun 2007
Posts: 865
Location: Sonoma County, CA, USA
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| Posted: Sun Feb 20, 2011 8:11 am Post subject: |
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Solving one for old time's sake...
| Code: | +-------------------+------------+----------------+
| 8 27 249 | 1 479 5 | 247 3 6 |
| 1247 5 124 | 6 47 3 | 2478 279 489 |
| 3479 367 3469 | 8 2 79 | 47 5 1 |
+-------------------+------------+----------------+
| 137 4 5 | 9 367 67 | 13 8 2 |
| 237 237 8 | 4 37 1 | 9 6 5 |
| 6 9 13 | 5 8 2 | 13 4 7 |
+-------------------+------------+----------------+
| 2349 2368 23469 | 7 1 69 | 5 29 389 |
| 39 1368 369 | 2 5 4 | 678 179 389 |
| 5 126 7 | 3 69 8 | 246 129 49 |
+-------------------+------------+----------------+ |
[1] Kite B128 (or FXW c16); r7c3<>9
[2] ALS r7c8|r9c579; r9c8<>9
[3] (4=9)r9c1 - (9=6)r9c5 - (6=6)r47c6 - (6=7)r45c5 - (7=4)r2c5; r2c9<>4
| Code: | +-----------------+----------+--------------+
| 8 27 9 | 1 47 5 | 247 3 6 |
| 1247 5 124 | 6 47 3 | 2478 27 9 |
| 347 36 346 | 8 2 9 | 47 5 1 |
+-----------------+----------+--------------+
| 13 4 5 | 9 6 7 | 13 8 2 |
| 27 27 8 | 4 3 1 | 9 6 5 |
| 6 9 13 | 5 8 2 | 13 4 7 |
+-----------------+----------+--------------+
| 24 38 24 | 7 1 6 | 5 9 38 |
| 9 1368 36 | 2 5 4 | 67 17 38 |
| 5 16 7 | 3 9 8 | 26 12 4 |
+-----------------+----------+--------------+ |
[4] 38UR r78c29; r3c2<>6
[5] BUG+1; r1c7=7 (or there is an XYW) |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Sun Feb 20, 2011 4:02 pm Post subject: |
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Taking them as I saw them, I had four steps
#1: Flightless AXY-wing 47-9 vertex(47)r2c5, pincers (49)r2c9 & (79)r3c6 with fin (8)r2c9; r9c9<>9=4
If xy-wing is true plus transport: (9)r3c6-r7c6=(9)r9c5
If fin is true: (8)r2c9-r2c7=(8-6)r8c7=(6-4)r9c7=(4-9)r9c9
#2: This opened up a xy-wing 26-9 vertex (26)r9c7; r7c6<>9
#3: Type 1 AUR(38)r78c29; r8c2<>38
#4: Either an xy-wing 2-47 with vertex (27)r1c2 or BUG+1 (247)r1c7 completes the puzzle.
In hindsight, the initial two steps could be replaced by an AXY-wing.
| Code: | *--------------------------------------------------------------------*
| 8 27 249 | 1 479 5 | 247 3 6 |
| 1247 5 124 | 6 47 3 | 2478 279 489 |
| 3479 367 3469 | 8 2 79 | 47 5 1 |
|----------------------+----------------------+----------------------|
| 137 4 5 | 9 367 67 | 13 8 2 |
| 237 237 8 | 4 37 1 | 9 6 5 |
| 6 9 13 | 5 8 2 | 13 4 7 |
|----------------------+----------------------+----------------------|
| 2349 2368 23469 | 7 1 6-9 | 5 #29 389 |
| 39 1368 369 | 2 5 4 | 678 179 389 |
| 5 126 7 | 3 #69 8 | 26(4) 129 49 |
*--------------------------------------------------------------------* |
AXY-wing 26-9 vertex (26)r9c7, pincers, marked #, (29)r7c8 & (69)r9c5 with fin (4)r9c7; r7c6<>9
If the fin is true: (4)r9c7-(4=7)r3c7-(7=9)r3c6
Ted |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Sun Feb 20, 2011 4:15 pm Post subject: |
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Hi Asellus,
Wonderful to see your post 
Missed your participation in the forum (and not just when we needed your expert explanations).
Hope to see you around more often...........
Ted |
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peterj
Joined: 26 Mar 2010
Posts: 974
Location: London, UK
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| Posted: Sun Feb 20, 2011 4:44 pm Post subject: |
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I used what Marty describes as 'an abomination'!! - and it perhaps what ted refers to in his post...
| Code: | Almost xy-wing(29-6) r7c8 fin (4)r9c7
(6=9)r7c6 - (9=7)r3c6 - (7=4)r3c7 - (4)r9c7=xywing(29-6)[(6)r9c7=r7c6] ; r9c5<>6
w-wing(27) (2=7)r1c2 - r3c1=r3c7 - (7=2)r2c8 ; r1c7<>2, r2c13<>2 |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Sun Feb 20, 2011 5:44 pm Post subject: Re: Puzzle 11/02/19 Difficult BBDB |
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| daj95376 wrote: | | Code: | +-----------------------+
| 8 . . | . . 5 | . . 6 |
| . 5 . | 6 . 3 | . . . |
| . . . | 8 2 . | . . 1 |
|-------+-------+-------|
| . 4 5 | 9 . . | . 8 2 |
| . . 8 | . . 1 | 9 6 . |
| 6 9 . | . 8 . | . 4 7 |
|-------+-------+-------|
| . . . | . 1 . | 5 . . |
| . . . | 2 5 4 | . . . |
| 5 . 7 | 3 . 8 | . . . |
+-----------------------+
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Play this puzzle online at the Daily Sudoku site |
Danny,
Do you have the date when this puzzle was originally posted? It seems that the level of talent has increased to the stage where this puzzle may not presently classify as a BBDBer.
Ted |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Sun Feb 20, 2011 5:51 pm Post subject: |
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XY-Chain running from r9c9 to r3c7; r2c9, r9c7<>4
XY-Wing (296); r9c5<>6
W-Wing (27); r1c7, r2c13<>2 |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Sun Feb 20, 2011 6:24 pm Post subject: |
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Asellus' first two moves are not needed. Step 3 can be seen as a W-wing with a pseudocell 47-79 = 49. After that, XY-wing, UR, and a BUG+1 or another XY-wing finish it off.
Keith |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Sun Feb 20, 2011 7:32 pm Post subject: Re: Puzzle 11/02/19 Difficult BBDB |
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| tlanglet wrote: | Do you have the date when this puzzle was originally posted? It seems that the level of talent has increased to the stage where this puzzle may not presently classify as a BBDBer.
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Ted, I base the BBDB classifier on the number of steps returned by my solver. If a puzzle has more than four steps listed, then I tag it as BBDB.
Previously, I would review most puzzles for extraneous steps before posting them. That involved a lot of work for a puzzle that ended up with one reply ... and it didn't use any of the steps found by my solver.
Now, I've grown lazy and usually review only puzzles with multiple comments (like this one). Here's my findings -- four steps:
| Code: | r1c6 2-String Kite <> 9 r7c3 extraneous
M-Wing 2A: (4=9)r9c9 - r9c5 = (9-4)r1c5 = (4)r2c5 => r2c9<>4
-or-
XY-Chain: (4=7)r3c7 =9r3c6 =6r7c6 =9r9c5 =4r9c9 => r2c9,r9c7<>4
<29+6> XY-Wing r7c8/r7c6+r9c7 <> 6 r9c5
<26+9> XY-Wing r9c7/r7c8+r9c5 <> 9 r7c6,r9c8 extraneous
r78c29 <38> UR Type 1.2224 <> 38 r8c2
BUG+1 = 7 r1c7
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