dailysudoku.com Forum Index dailysudoku.com
Discussion of Daily Sudoku puzzles
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

Nice puzzle

 
Post new topic   Reply to topic    dailysudoku.com Forum Index -> Other puzzles
View previous topic :: View next topic  
Author Message
ravel



Joined: 21 Apr 2006
Posts: 536

PostPosted: Thu Jul 05, 2007 10:54 am    Post subject: Nice puzzle Reply with quote

This is a puzzle, that i found from my search for minimal puzzles with 37 givens:
Code:
 +-------+-------+-------+
 | 1 . . | 4 5 . | . 8 . |
 | 4 . 7 | 1 8 . | . . 3 |
 | 8 . . | 3 2 7 | 1 . 4 |
 +-------+-------+-------+
 | 2 7 . | 6 3 . | 4 . 5 |
 | 3 . . | . 7 . | . 2 6 |
 | . . . | . . . | 3 . . |
 +-------+-------+-------+
 | . 1 . | . . . | . . 2 |
 | . . 2 | 7 1 . | . . . |
 | 7 8 . | 2 6 . | 5 . 1 |
 +-------+-------+-------+
It can be solved with 2 x-wings, 1 xyz-wing, 4 xy-wings and one W Wing (which was called Y Wing on the players forum).
Back to top
View user's profile Send private message
Marty R.



Joined: 12 Feb 2006
Posts: 5176
Location: Rochester, NY, USA

PostPosted: Fri Jul 06, 2007 5:03 am    Post subject: Reply with quote

I'm throwing in the towel. The techniques you used are not exactly rocket science, but I'm obviously missing something. I don't recall a puzzle on which I've done so much and gotten so little in return. I've used eight techniques and solved only eight cells. What I've used are five X-Wings, including two Finned, an XY, a W and an XYZ. All those 34s in the lower band are bugging me too.

Code:

+------------+----------+------------+
| 1  23  36  | 4  5 69  | 279 8   79 |
| 4  25  7   | 1  8 69  | 29  56  3  |
| 8  9   56  | 3  2 7   | 1   56  4  |
+------------+----------+------------+
| 2  7   189 | 6  3 18  | 4   19  5  |
| 3  45  145 | 9  7 15  | 8   2   6  |
| 59 6   18  | 58 4 2   | 3   17  79 |
+------------+----------+------------+
| 56 1   34  | 58 9 348 | 67  347 2  |
| 69 345 2   | 7  1 345 | 69  34  8  |
| 7  8   349 | 2  6 34  | 5   349 1  |
+------------+----------+------------+

Play this puzzle online at the Daily Sudoku site
Back to top
View user's profile Send private message
ravel



Joined: 21 Apr 2006
Posts: 536

PostPosted: Fri Jul 06, 2007 7:24 am    Post subject: Reply with quote

Hi Marty,

you already did it ! One last xy-wing and the puzzle is solved. I cant tell you, where it is Smile
Back to top
View user's profile Send private message
Mogulmeister



Joined: 03 May 2007
Posts: 695

PostPosted: Fri Jul 06, 2007 2:35 pm    Post subject: Reply with quote

...or if you prefer there is an X-Y chain in boxes 4,5 &6 making an elimination in box 6. Look at the bivalues. Smile
Back to top
View user's profile Send private message
Marty R.



Joined: 12 Feb 2006
Posts: 5176
Location: Rochester, NY, USA

PostPosted: Fri Jul 06, 2007 3:19 pm    Post subject: Reply with quote

ravel wrote:
Hi Marty,

you already did it ! One last xy-wing and the puzzle is solved. I cant tell you, where it is Smile


Ravel, I'm ready for suicide. I don't know how much time I've spent looking for XY-Wings, but if I knew, I'd be too embarrassed to tell you. Embarassed

MM, ditto for XY-Chains. Embarassed
Back to top
View user's profile Send private message
Mogulmeister



Joined: 03 May 2007
Posts: 695

PostPosted: Fri Jul 06, 2007 3:35 pm    Post subject: Reply with quote

Isn't that the truth ! I often leave a puzzle and then come back to it and sometimes I see a solution immediately - sometimes it is so obvious that I have missed it because I'm looking for a more involved answer.

Take yours - I saw the more involved X-Y chain first and then had to look furiously for ravel's suggested x-y wing, which lets face it, is the shortest x-y chain possible !
Back to top
View user's profile Send private message
Marty R.



Joined: 12 Feb 2006
Posts: 5176
Location: Rochester, NY, USA

PostPosted: Fri Jul 06, 2007 3:56 pm    Post subject: Reply with quote

Update, 35 minutes later. Knowing it was there, I found the XY-Chain and immediately noticed the XY-Wing in the same cells. I miss XY-Chains all the time, but I search systematically for XY-Wings, checking each box for every bivalue cell and seeing if there's a wing. I don't how I missed that. Multiple times, I might add.

A good puzzle for me, one that forces you to work at it, but doesn't require arcane techniques.
Back to top
View user's profile Send private message
jLo



Joined: 30 Apr 2007
Posts: 55

PostPosted: Fri Jul 06, 2007 4:53 pm    Post subject: Reply with quote

There are a couple of W-wings that eliminate the need for any XY-wings or
XY-chains. X-wing, W-wing, XYZ-wing, X-wing, W-wing did it for me (along
with some naked-pairs, hidden pairs, and box-line eliminations).
Back to top
View user's profile Send private message Yahoo Messenger
Mogulmeister



Joined: 03 May 2007
Posts: 695

PostPosted: Fri Jul 06, 2007 5:18 pm    Post subject: Reply with quote

Which were the pairs you used for the 2 W-Wings Jlo ? I assume you put the 56's to good use ?
Back to top
View user's profile Send private message
jLo



Joined: 30 Apr 2007
Posts: 55

PostPosted: Fri Jul 06, 2007 6:43 pm    Post subject: Reply with quote

Quote:

Which were the pairs you used for the 2 W-Wings Jlo ? I assume you put the 56's to good use ?


The first was <89>s, the second was <18>s.
Back to top
View user's profile Send private message Yahoo Messenger
Mogulmeister



Joined: 03 May 2007
Posts: 695

PostPosted: Fri Jul 06, 2007 6:49 pm    Post subject: Reply with quote

Sorry for being dense, but I don't see the 89 pairs (I'm looking at Marty's grid).
Back to top
View user's profile Send private message
jLo



Joined: 30 Apr 2007
Posts: 55

PostPosted: Fri Jul 06, 2007 7:25 pm    Post subject: Reply with quote

Quote:

Sorry for being dense, but I don't see the 89 pairs (I'm looking at Marty's grid).



You'll note that Marty said one of the moves he used to get to that grid was a
W-wing. It was <89>s at R5C7 and R8C9. It opens up the single <8>s in block
6 and block 9 (as reflected in his grid.)
Back to top
View user's profile Send private message Yahoo Messenger
Mogulmeister



Joined: 03 May 2007
Posts: 695

PostPosted: Fri Jul 06, 2007 8:03 pm    Post subject: Reply with quote

Thanks jlo- I was looking at the post 89 grid ! Very Happy
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    dailysudoku.com Forum Index -> Other puzzles All times are GMT
Page 1 of 1

 
Jump to:  
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