| View previous topic :: View next topic |
| Author |
Message |
daj95376
Joined: 23 Aug 2008
Posts: 3854
|
 Posted: Fri Apr 30, 2010 8:24 am Post subject: Puzzle 10/04/30 (E) BBDB |
 |
|
| Code: | +-----------------------+
| 6 . . | 3 1 2 | 5 . . |
| . . . | . 4 . | . 7 9 |
| . . . | . . 9 | 1 . . |
|-------+-------+-------|
| 4 . . | 2 . . | . . 7 |
| 2 1 . | . . . | 3 . . |
| 3 . 7 | . . . | . 9 . |
|-------+-------+-------|
| 7 . 5 | . 2 . | . . . |
| . 3 . | . . 7 | . 2 . |
| . 4 . | 9 . . | . . 5 |
+-----------------------+
|
Play this puzzle online at the Daily Sudoku site |
|
| Back to top |
|
 |
Mogulmeister
Joined: 03 May 2007
Posts: 1151
|
| Posted: Sat May 01, 2010 4:24 pm Post subject: |
|
|
| Quote: | 1. XYZ Wing (or finned XY) <136> vertex at r7c9 : r7c8<>3
2. A 4 square ALS and took me hours: r4c58 SET X {1,3,5}
then the larger set which is in 79c8 r8c79 SET Z {1,3,4,6,8}
Restricted Common is 1s in column 8 and common candidate 3 in r9c5 is eliminated.
(Diagram to follow)
Puzzle solved (I think?) |
|
|
| Back to top |
|
|
Mogulmeister
Joined: 03 May 2007
Posts: 1151
|
|
| Back to top |
|
|
peterj
Joined: 26 Mar 2010
Posts: 974
Location: London, UK
|
| Posted: Sat May 01, 2010 5:06 pm Post subject: |
|
|
Awesome ALS - great job! I am getting some results looking for the simpler ALS-XZ types, but these bigger ones are tough to find.
You have to kiss a lot of frogs! An awful lots of ALSs but most of them cant be used or arent useful. |
|
| Back to top |
|
|
Mogulmeister
Joined: 03 May 2007
Posts: 1151
|
| Posted: Sat May 01, 2010 5:27 pm Post subject: |
|
|
Absolutely !!
 |
|
| Back to top |
|
|
Mogulmeister
Joined: 03 May 2007
Posts: 1151
|
| Posted: Sat May 01, 2010 10:03 pm Post subject: |
|
|
| I think productive ALS spotting is very hard and time consuming but the satisfaction of finding one is tremendous. I totally agree about the frogs - I have kissed many. |
|
| Back to top |
|
|
Mogulmeister
Joined: 03 May 2007
Posts: 1151
|
| Posted: Sun May 02, 2010 10:55 am Post subject: |
|
|
OK - there is a simpler one stepper although (for me) less fun than the ALS:
Look at the generalised remote pair <36> in green. They toggle, if one is 3 the other is 6 and so perform a double elimination of 3 and 6 in r9c8 which solves the puzzle! (6=3)r9c5-(3=5)r4c5-(5=1)r4c8-(1=2)r6c9-(2=3)r3c9-(3=6)r3c8
 |
|
| Back to top |
|
|
daj95376
Joined: 23 Aug 2008
Posts: 3854
|
| Posted: Sun May 02, 2010 1:46 pm Post subject: |
|
|
| Mogulmeister wrote: | | Look at the generalised remote pair <36> in green. They toggle, if one is 3 the other is 6 and so perform a double elimination of 3 and 6 in r9c8 ... |
What's to prevent them both from being <6> ... other than the solution ? |
|
| Back to top |
|
|
Mogulmeister
Joined: 03 May 2007
Posts: 1151
|
| Posted: Mon May 03, 2010 9:06 pm Post subject: |
|
|
Nothing Danny and quite right.
It's a toggle from 3 => 6 at either end of the chain but 6 => 3 can not be guaranteed alone so actually a false positive that provided a result.
The subsequent collateral damage that results in a correct solution makes this a "quasi" toggle!!  |
|
| Back to top |
|
|
|
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
