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 

DB Saturday Puzzle - October 7, 2006

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



Joined: 19 Sep 2005
Posts: 3184
Location: near Detroit, Michigan, USA

PostPosted: Sat Oct 07, 2006 1:29 pm    Post subject: DB Saturday Puzzle - October 7, 2006 Reply with quote

Here it is. I won't be looking at it today.

Keith
Code:
Puzzle: DB100706  ******
+-------+-------+-------+
| . 5 . | . . . | . 9 . |
| 1 . . | 8 . 9 | . . . |
| 7 . . | 4 . . | . . 6 |
+-------+-------+-------+
| . 9 . | . 4 7 | 8 . 3 |
| . . . | . 3 . | . . . |
| 4 . 7 | 2 8 . | . 6 . |
+-------+-------+-------+
| 5 . . | . . 2 | . . 4 |
| . . . | 5 . 4 | . . 7 |
| . 6 . | . . . | . 3 . |
+-------+-------+-------+
Back to top
View user's profile Send private message
Marty R.



Joined: 12 Feb 2006
Posts: 5180
Location: Rochester, NY, USA

PostPosted: Sat Oct 07, 2006 3:27 pm    Post subject: Reply with quote

This one wasn't as challenging as the one two weeks ago. Basic stuff plus a couple of Type 4 rectangles, which I'm not sure were necessary for the solution. There was also a point at which I think remote pairs (25) could have been used, but they weren't necessary.
Back to top
View user's profile Send private message
TexCat



Joined: 07 Jul 2006
Posts: 31

PostPosted: Sat Oct 07, 2006 5:07 pm    Post subject: Reply with quote

My first Saturday without resorting to trial & error! Though it took me quite a while.
Back to top
View user's profile Send private message
ravel



Joined: 21 Apr 2006
Posts: 536

PostPosted: Sat Oct 07, 2006 7:27 pm    Post subject: Reply with quote

Code:
 *-----------------------------------------------------------*
 | 23    5     23    | 167   17    16    | 4     9     8     |
 | 1     4     6     | 8     25    9     | 3     7     25    |
 | 7     8     9     | 4     25    3     | 125   125   6     |
 |-------------------+-------------------+-------------------|
 |@26    9    -125   |@16    4     7     | 8     125   3     |
 | 268  @12    1258  | 9     3     156   | 7     4     125   |
 | 4     3     7     | 2     8     15    | 159   6     159   |
 |-------------------+-------------------+-------------------|
 | 5     7     18    | 3    #69    2     |#69    18    4     |
 | 2389  12    1238  | 5    #169   4     |#1269  128   7     |
 | 29    6     4     | 17    179   8     | 1259  3     1259  |
 *-----------------------------------------------------------*
Many ways to solve it. In this situation either the xy-wing in the cells marked @ or the UR4 (marked #), which (because of the strong link of 6 in row 8) eliminates 9 from r8c57.
Additional:
This is also a UR3, because 12 are the extra candidates and we have 12 in r8c2, so 12 can be eliminated from r8c138.
Or: Since r8c2=12 and r8c8=128, 128 can be eliminated from r8c13.
And there is a UR4 for 23 in r18c13, which eliminates 2 from r8c13 (not a big help).
PS: I forgot to mention, that Simple Sudoku eliminates the 2 in r8c8 with coloring (r8c2-r5c2-r5c9-r4c8), but needed the xy-wing later.
Back to top
View user's profile Send private message
TexCat



Joined: 07 Jul 2006
Posts: 31

PostPosted: Sat Oct 07, 2006 10:08 pm    Post subject: Reply with quote

I solved it with the xy-wing. My first ever! I really find these hard to find.
Back to top
View user's profile Send private message
Marty R.



Joined: 12 Feb 2006
Posts: 5180
Location: Rochester, NY, USA

PostPosted: Sun Oct 08, 2006 5:19 am    Post subject: Reply with quote

TexCat wrote:
I solved it with the xy-wing. My first ever! I really find these hard to find.

Congratulations. Always great to use a technique for the first time. My biggest problem with the XY-Wing was always forgetting to look for them. I'll still miss SOME, but if I don't look, then I'll miss them ALL.
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