dailysudoku.com :: View topic - last week's extreme #60

dailysudoku.com
Discussion of Daily Sudoku puzzles

FAQ

Memberlist

Usergroups

Profile

last week's extreme #60

dailysudoku.com Forum Index -> Other puzzles

View previous topic :: View next topic

Author

Message

storm_norm

Joined: 18 Oct 2007
Posts: 1741

Posted: Tue Nov 20, 2007 6:09 pm Post subject: last week's extreme #60

this is from sudoku.org.uk, which has changed its address.
basics get to here:

Code:

------------------------------------------------------------------------------|
| 8 4 9 | 53 2 53 | 1 67 67 |
| 5 6 2 | 1 7 9 | 3 4 8 |
| 1 7 3 | 468 48 468 | 5 9 2 |
------------------------------------------------------------------------------|
| 9 238 16 | 3468 1348 7 | 2468 1268 5 |
| 367 2358 1567 | 34568 13458 34568 | 9 12678 1467 |
| 4 58 1567 | 9 158 2 | 68 1678 3 |
------------------------------------------------------------------------------|
| 2 1 4567 | 34578 3458 3458 | 468 368 9 |
| 37 9 47 | 23478 6 1348 | 248 5 14 |
| 36 35 8 | 2345 9 1345 | 7 1236 146 |
------------------------------------------------------------------------------|

norm

keith

Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA

Posted: Tue Nov 20, 2007 9:16 pm Post subject:

There is a chain in R89 that eliminates <5> in R9C6. Then, no more chains. (According to Sudoku Susser.) Keith

ravel

Joined: 21 Apr 2006
Posts: 536

Posted: Wed Nov 21, 2007 8:22 am Post subject:

Code:

------------------------------------------------------------------------------|
| 8 4 9 | 53 2 53 | 1 C67 C67 |
| 5 6 2 | 1 7 9 | 3 4 8 |
| 1 7 3 | 468 48 468 | 5 9 2 |
------------------------------------------------------------------------------|
| 9 238 16 | 3468 1348 7 | 2468 1268 5 |
|C367 2358 1567 | 34568 13458 34568 | 9 12678 C1467 |
| 4 B58 1567 | 9 158 2 |B68 1678 3 |
------------------------------------------------------------------------------|
| 2 1 A4567 | 34578 3458 3458 |B468 C368 9 |
|-37 9 47 | 23478 6 1348 | 248 5 14 |
|A36 B35 8 | 2345 9 1345 | 7 1236 146 |
------------------------------------------------------------------------------|

This seems to be an awkward puzzle, that does not allow an elegant solution (at least i cant see one). You have the choice between a couple of shorter chains or a long and complicated one like this (indeed a triple forcing chain):
r8c1=3 => r9c1=6 => r7c3<>6
r8c1=3 => r9c2=5 => r6c2=8 => r6c7=6 => r7c7<>6
r8c1=3 => r5c1=7 => r5c9<>7 => r1c9=7 => r1c8=6 => r7c8<>6
So all 6's in row 7 are killed, therefore r8c1 cannot be 3.

Display posts from previous:

	dailysudoku.com Forum Index -> Other puzzles	All times are GMT
Page 1 of 1

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