View previous topic :: View next topic |
Author |
Message |
daj95376
Joined: 23 Aug 2008 Posts: 3854
|
Posted: Fri Nov 28, 2008 10:36 pm Post subject: Set A Puzzle 30 |
|
|
Code: | +-----------------------+
| 5 . . | . . . | 7 . 9 |
| . 1 3 | 7 . . | 8 . 4 |
| . 4 . | . . . | . . . |
|-------+-------+-------|
| . 3 . | 4 . . | . 7 5 |
| . . . | . . . | . . . |
| . . . | . . 5 | 3 8 1 |
|-------+-------+-------|
| 3 8 . | . . 6 | . . . |
| . . . | 3 . 1 | . 4 8 |
| 1 9 . | 2 . 4 | . 5 . |
+-----------------------+
|
Play this puzzle online at the Daily Sudoku site |
|
Back to top |
|
|
tlanglet
Joined: 17 Oct 2007 Posts: 2468 Location: Northern California Foothills
|
Posted: Sat Nov 29, 2008 3:00 am Post subject: |
|
|
I found a three-step solution: An ER followed by two xy-wings.
Hint: Quote: | ER on <6> in box2 with strong link on <6> in row6, a xy-wing on <289> and then on <689>. |
Ted |
|
Back to top |
|
|
storm_norm
Joined: 18 Oct 2007 Posts: 1741
|
Posted: Tue Dec 09, 2008 10:14 pm Post subject: |
|
|
that ER that Marty mentioned had me evaluating this puzzle again and this came up.
notice the "*" marked cells belown contain the almost UR {2,5} in r58c23
Code: | .------------------.------------------.------------------.
| 5 26 268 | 168 4 238 | 7 13 9 |
| 29 1 3 | 7 5 29 | 8 6 4 |
| 7 4 689 | 1689 16 389 | 5 13 2 |
:------------------+------------------+------------------:
| 689 3 169 | 4 16 89 | 2 7 5 |
| 28 *25 *125 | 18 3 7 | 4 9 6 |
| 4 7 69 | 69 2 5 | 3 8 1 |
:------------------+------------------+------------------:
| 3 8 4 | 5 9 6 | 1 2 7 |
| 26 *256 *256 | 3 7 1 | 9 4 8 |
| 1 9 7 | 2 8 4 | 6 5 3 |
'------------------'------------------'------------------' |
notice also that an inference can be made.
if the 1 in r5c3 is not there then the 6's in r8c23 have to be true. and vice versa. this is a strong link, they both can't be false. (1)r5c3 = (6)r8c23...ok?
lets put this little chunk to work
Code: | .------------------.------------------.------------------.
| 5 26 268 | 168 4 238 | 7 13 9 |
| 29 1 3 | 7 5 29 | 8 6 4 |
| 7 4 689 | 1689 16 389 | 5 13 2 |
:------------------+------------------+------------------:
|#689 3 169 | 4 #16 89 | 2 7 5 |
| 28 25 #125 |-18 3 7 | 4 9 6 |
| 4 7 69 | 69 2 5 | 3 8 1 |
:------------------+------------------+------------------:
| 3 8 4 | 5 9 6 | 1 2 7 |
|#26 #256 #256 | 3 7 1 | 9 4 8 |
| 1 9 7 | 2 8 4 | 6 5 3 |
'------------------'------------------'------------------' |
now we can form a w-wing yep. see the strong links on 6 in column 1?
we now have a w-wing {1,6} via strong link on 6 in column 1. this connects our pseudocell {1,6} to the {1,6} in r4c5. 1's are the pincers eliminating the 1 in r5c4.
singles to finish.
hopefully this image will be helpful.
I circled the w-wing pair in green ! and I connected the links on 6 in blue, the red is the pincer elimination.
what this shows is how the {1,6} pseudocell is formed via the almost UR and how they can be encompassed because they are part of the UR structure thus forming the strong link necessary, like a bivalue cell
I will take a shot at notating this.
(25UR)r58c23[(1)r5c3 = (6)r8c23] - (6)r8c1 = (6)r4c1 - (6=1)r4c5; r5c4 <> 1 |
|
Back to top |
|
|
|
|
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|