dailysudoku.com :: View topic - Free Press Dec 3, 2010

dailysudoku.com
Discussion of Daily Sudoku puzzles

FAQ

Memberlist

Usergroups

Profile

Free Press Dec 3, 2010

dailysudoku.com Forum Index -> Other puzzles

View previous topic :: View next topic

Author

Message

keith

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

Posted: Fri Dec 03, 2010 1:42 pm Post subject: Free Press Dec 3, 2010

Not yet started ...

Code:

Puzzle: FP031210
+-------+-------+-------+
| . . . | 7 . 8 | . . . |
| 6 . . | . . . | 1 . 3 |
| . 4 . | . 5 . | . 2 . |
+-------+-------+-------+
| . . 5 | . 2 1 | . 7 . |
| 7 . . | . . . | . . 9 |
| . . . | 4 8 . | 5 . . |
+-------+-------+-------+
| . 3 . | . . . | . 9 . |
| 2 . 9 | . 6 . | . . 7 |
| . . . | 8 . 2 | . . . |
+-------+-------+-------+

Play this puzzle online at the Daily Sudoku site

Keith

Marty R.

Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA

Posted: Fri Dec 03, 2010 7:59 pm Post subject:

Brick-wall time after a promising start of 6-cell DP, W-Wing and Skyscraper. With what's left I couldn't even get a Medusa trap.

Code:

+-------------+---------+------------+
| 5 2 3 | 7 1 8 | 9 46 46 |
| 6 78 78 | 2 4 9 | 1 5 3 |
| 9 4 1 | 36 5 36 | 7 2 8 |
+-------------+---------+------------+
| 348 68 5 | 69 2 1 | 348 7 46 |
| 7 18 248 | 56 3 56 | 248 148 9 |
| 13 9 26 | 4 8 7 | 5 136 12 |
+-------------+---------+------------+
| 148 3 468 | 15 7 45 | 246 9 12 |
| 2 5 9 | 13 6 34 | 48 148 7 |
| 14 167 467 | 8 9 2 | 346 134 5 |
+-------------+---------+------------+

Play this puzzle online at the Daily Sudoku site

peterj

Joined: 26 Mar 2010
Posts: 974
Location: London, UK

Posted: Fri Dec 03, 2010 9:28 pm Post subject:

Marty, from your grid there is an m-wing(26) that finishes it off...

Code:

m-wing(26) ; (2=6)r6c3 - r7c3=(6-2)r7c7=r5c7 ; r5c3<>2, r6c9<>2

.. and also an s-wing(26) pivotted on the same bivalue...

Marty R.

Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA

Posted: Fri Dec 03, 2010 10:09 pm Post subject:

Peter, you've been bailing me out a lot lately. I've executed uncounted M-Wings but the ones like this, with a non-bivalue cell, are just not prominent on my radar. Unfortunately, I haven't seen an explanation of an S-Wing that I understand.

keith

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

Posted: Sat Dec 04, 2010 2:45 am Post subject:

Marty R. wrote:

Peter, you've been bailing me out a lot lately. I've executed uncounted M-Wings but the ones like this, with a non-bivalue cell, are just not prominent on my radar.

Unfortunately, I haven't seen an explanation of an S-Wing that I understand.

Marty,

These M-wings are easy to find and quite powerful, but the recipe to find them is different than the original M-wing.

Recipe: Start in any bivalue cell, XY.

Through coloring, figure out all the cells where X in XY causes X.

Do any of those cells contain Y? If so, is there a strong link on Y?

In this example:

Code:

+-------------+---------+------------+
| 5 2 3 | 7 1 8 | 9 46# 46@|
| 6 78 78 | 2 4 9 | 1 5 3 |
| 9 4 1 | 36 5 36 | 7 2 8 |
+-------------+---------+------------+
| 348 68@ 5 | 69 2 1 | 348 7 46#|
| 7 18 248 | 56 3 56 | 248 148 9 |
| 13 9 26# | 4 8 7 | 5 136@ 1-2|
+-------------+---------+------------+
| 148 3 468@| 15 7 45 |246# 9 12$|
| 2 5 9 | 13 6 34 | 48 148 7 |
| 14 167# 467@| 8 9 2 |346@ 134 5 |
+-------------+---------+------------+

6 in R6C3 causes 6 in the cells marked #, not 6 in the cells marked @. Note that R7C7 is #, and it contains a 2. Then, there is a strong link on 2 to R7C9. You can eliminate 2 in R6C9 as shown.

So, the logic is,

1.) XY may be Y.

2.) XY may be X. If so, it forces X in another cell aXY.
Then, if not Y in aXY forces Y in a third cell, cY, the first and third cells, XY and cY are pincers in Y.

The recipe is not difficult, but it does depend on your ability to do coloring "in your head", so to speak.

This is a lot different than my original M-wing, where the recipe was to figure out how two bivalue cells with identical candidates might be connected.

Keith

tlanglet

Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills

Posted: Sat Dec 04, 2010 3:48 pm Post subject:

Code after basics:

Code:

*-----------------------------------------------------------*
| 35 25 23 | 7 1 8 | 9 46 46 |
| 6 78 78 | 2 4 9 | 1 5 3 |
| 9 4 1 | 36 5 36 | 7 2 8 |
|-------------------+-------------------+-------------------|
| 348 *68 5 | 9 2 1 |*3468 7 46 |
| 7 128 248 | 56 3 56 | 248 148 9 |
| 13 9 236 | 4 8 7 | 5 136 12 |
|-------------------+-------------------+-------------------|
| 1458 3 468 | 15 7 45 |@2468 9 125 |
| 2 158 9 | 135 6 345 | 48 148 7 |
| 145 *1567 467 | 8 9 2 |*346 1346 15 |
*-----------------------------------------------------------*

Look at the finned x-wing (6)r49c27, marked *, with fin (6)r7c7 marked @. The normal finned x-wing deletion is r9c8<>6, which is a non-productive move.

However, if we treat the fin as a Kraken fin then
If x-wing is true; r4c9,r9c38<>6
If fin is true: (6)r7c7-(2)r7c7=r5c7-r5c23=(2-6)r6c3=(6)r4c2; r4c9<>6 which completes the puzzle in one step.

Ted

daj95376

Joined: 23 Aug 2008
Posts: 3854

Posted: Sun Dec 05, 2010 5:19 am Post subject:

Code:

after basics
+--------------------------------------------------------------+
| 35 25 23 | 7 1 8 | 9 46 46 |
| 6 78 78 | 2 4 9 | 1 5 3 |
| 9 4 1 | 36 5 36 | 7 2 8 |
|--------------------+--------------------+--------------------|
| 348 68 5 | 9 2 1 | 3468 7 46 |
| 7 128 248 | 56 3 56 | 248 148 9 |
| 13 9 236 | 4 8 7 | 5 136 12 |
|--------------------+--------------------+--------------------|
| 1458 3 468 | 15 7 45 | 2468 9 125 |
| 2 158 9 | 135 6 345 | 48 148 7 |
| 145 1567 467 | 8 9 2 | 346 1346 15 |
+--------------------------------------------------------------+
# 66 eliminations remain

Code:

2x strong link in <2>
+-----------------------------------+
| . 2 2 | . . . | . . . |
| . . . | 2 . . | . . . |
| . . . | . . . | . 2 . |
|-----------+-----------+-----------|
| . . . | . 2 . | . . . |
| . 2 2 | . . . | 2 . . |
| . . 2a | . . . | . . 2b | <- strong link #1
|-----------+-----------+-----------|
| . . . | . . . | 2d . 2c | <- strong link #2
| 2 . . | . . . | . . . |
| . . . | . . 2 | . . . |
+-----------------------------------+

1x strong link in <6>
+-----------------------------------+
| . . . | . . . | . 6 6 |
| 6 . . | . . . | . . . |
| . . . | 6 . 6 | . . . |
|-----------+-----------+-----------|
| . 6 . | . . . | 6 . 6 |
| . . . | 6 . 6 | . . . |
| . . -6 | . . . | . 6 . |
|-----------+-----------+-----------|
| . . 6e | . . . | 6d . . | <- strong link #3
| . . . | . 6 . | . . . |
| . 6 6 | . . . | 6 6 . |
+-----------------------------------+

Voila, your simplest/classic ...

Code:

a b c d e
L2-Wing: (2)r6c3 = r6c9 - r7c9 = (2-6)r7c7 = (6)r7c3 => r6c3<>6

No, I didn't find this manually. Sad

keith

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

Posted: Sun Dec 05, 2010 6:13 am Post subject:

So, Now I have to learn about S-wings and L-wings? Keith

Marty R.

Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA

Posted: Sun Dec 05, 2010 6:19 am Post subject:

Quote:

Now I have to learn about S-wings and L-wings?

No, you can remain ignorant like someone you know. Laughing

daj95376

Joined: 23 Aug 2008
Posts: 3854

Posted: Sun Dec 05, 2010 6:35 am Post subject:

keith wrote:

So,

Now I have to learn about S-wings and L-wings? Crying or Very sad

No. I'm just impressed by such patterns and though enough time had passed (since the puzzle was posted) to share it with others.

Normally, there are W-Wings and M-Wings along with S-Wings and L-Wings. So I wouldn't consider the latter solutions. However, only the L-Wings provided single-stepper solutions in this puzzle.

Regards, Danny

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