| View previous topic :: View next topic |
| Author |
Message |
daj95376
Joined: 23 Aug 2008
Posts: 3854
|
 Posted: Tue Apr 13, 2010 8:42 pm Post subject: Puzzle 10/04/13 (B) |
 |
|
| Code: | +-----------------------+
| . . . | 6 4 . | 2 3 . |
| . 4 . | . . . | . . 6 |
| . . . | . . 3 | . . . |
|-------+-------+-------|
| 1 . . | 3 . . | . . . |
| 2 . . | . . 8 | . 6 . |
| . . 8 | . 7 5 | 1 . . |
|-------+-------+-------|
| 6 . . | . . 9 | 4 2 8 |
| 9 . . | . 3 . | 6 7 . |
| . 5 . | . . . | 3 . . |
+-----------------------+
|
Play this puzzle online at the Daily Sudoku site
| Hint wrote: | XYZ-Wing possible.
|
|
|
| Back to top |
|
 |
tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
|
| Posted: Wed Apr 14, 2010 3:23 am Post subject: |
|
|
Another nice two stepper.
| Quote: | ALS[(17)r12c6 = (2)r2c6]r12c6 - (2=1)r2c3 - r3c2 = (1)r8c2; r8c6<>1,
xy-wing 24-6 with vertex in r8c6. |
Ted |
|
| Back to top |
|
|
Mogulmeister
Joined: 03 May 2007
Posts: 1151
|
| Posted: Wed Apr 14, 2010 6:29 am Post subject: |
|
|
The key to this puzzle is removing the 1 at r8c6. The puzzle then collapses on a simple <246> XY-wing as Ted has shown. He called it an ALS (which it is) which removes it. I looked at it diagrammatically:
I saw an extension of an x-chain on 1s idea, also very simple:
Start the chain as 2 (ie not 1) and r12c6 becomes a locked pair and r8c6 as 1 is toast.
(1=2)r8c2-r3c2=r2c3-(2=17)r12c6-(1)r8c6 so r8c6 <>1
Same result just a slightly dfferent way of looking at it.
Green for "is 2" Orange for "not 2"
 |
|
| Back to top |
|
|
Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
|
| Posted: Thu Apr 15, 2010 4:56 am Post subject: |
|
|
| It was a BBDB for me, taking seven moves. |
|
| Back to top |
|
|
daj95376
Joined: 23 Aug 2008
Posts: 3854
|
| Posted: Thu Apr 15, 2010 5:53 am Post subject: |
|
|
My solver's VH+ solution is deceptively difficult in reality.
| Code: | c26\r38 Sashimi X-Wing <> 1 r3c45 (grouped Skyscraper)
<27+1> XYZ-Wing r2c6/r1c6+r2c3 <> 1 r2c45 sufficient
<89+5> XYZ-Wing r3c7/r2c8+r3c4 <> 5 r3c8
<24+6> XY-Wing r8c6/r4c6+r9c5 <> 6 r4c5,r9c6
|
Rambling: On Mogulmeister's colored grid, I also noticed r2c6=12|7. The <12> formed a remote pair elimination of r8c6<>12. The selection r2c6=7 forced r1c6=1 and r8c6<>1. Either way, r8c6<>1. |
|
| Back to top |
|
|
Mogulmeister
Joined: 03 May 2007
Posts: 1151
|
| Posted: Thu Apr 15, 2010 11:10 am Post subject: |
|
|
| What does the "sufficient" from your solver indicate Danny ? |
|
| Back to top |
|
|
daj95376
Joined: 23 Aug 2008
Posts: 3854
|
| Posted: Thu Apr 15, 2010 12:14 pm Post subject: |
|
|
| Mogulmeister wrote: | | What does the "sufficient" from your solver indicate Danny ? |
I often (manually) add comments to my solver's output when I post it. In this case, I added the comment "sufficient" to indicate that only the first XYZ-Wing is needed. My solver doesn't stop searching when it first encounters an elimination while processing a particular technique. It finds all XYZ-Wings present before returning any results. You don't want to see its output when it finds a turbot fish pattern. 
Regards, Danny |
|
| Back to top |
|
|
|
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
