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 

august 18 very hard

 
Post new topic   Reply to topic    dailysudoku.com Forum Index -> Daily Sudoku puzzles
View previous topic :: View next topic  
Author Message
oaxen



Joined: 10 Jul 2006
Posts: 96

PostPosted: Tue Aug 22, 2006 6:51 pm    Post subject: august 18 very hard Reply with quote

After solving the "easy ones (20 units)"I got stucked and asked for a hint.
received "5" on c8r3. Why? I canīt see the logic in that choice. Can somebody tell me or do I have to write down the situation as far as I got
[/list]
Back to top
View user's profile Send private message Visit poster's website
TKiel



Joined: 22 Feb 2006
Posts: 292
Location: Kalamazoo, MI

PostPosted: Wed Aug 23, 2006 2:37 am    Post subject: Reply with quote

If I've done this right, at that point in the puzzle the candidates for r3c8 are 2, 5 & 8. There is an X-wing on 2 in row 6 & 7 that removes that digit and the 8 can be excluded because the 8 in row 2 must be in box 3 (which I think would make it a box/box interaction) and can thus be excluded from all other cells in that same box.
Back to top
View user's profile Send private message
oaxen



Joined: 10 Jul 2006
Posts: 96

PostPosted: Wed Aug 23, 2006 7:06 am    Post subject: Reply with quote

Thank you Tracy, that was not too easy to find out

Lars/Oaxen
Back to top
View user's profile Send private message Visit poster's website
Golfgal



Joined: 31 Jul 2006
Posts: 7

PostPosted: Wed Aug 23, 2006 11:33 am    Post subject: 8/18 Reply with quote

found the x-wing BUT unsure of what 2 in boxes 3, 6 & 9 could be removed

this is what i have

700 020 361
140 763 {289}{2589}{28}
306 900 4{25}7
238 679 514
400 000 {268}{238}{268}
651 048 7{23}9
064 007 1{29}3
000 130 {689}4{68}
813 090 {26}75
Back to top
View user's profile Send private message Send e-mail
TKiel



Joined: 22 Feb 2006
Posts: 292
Location: Kalamazoo, MI

PostPosted: Wed Aug 23, 2006 12:00 pm    Post subject: Reply with quote

This is the point at which the X-wing occurred.

Code:

 *-----------------------------------------------------------*
 | 7     89    59    | 458   2     45    | 3     6     1     |
 | 1     4     259   | 7     6     3     | 289   2589  28    |
 | 3     28    6     | 9     158   15    | 4     258   7     |
 |-------------------+-------------------+-------------------|
 | 2     3     8     | 6     7     9     | 5     1     4     |
 | 4     79    79    | 235   15    125   | 268   238   268   |
 | 6     5     1     |[23]   4     8     | 7    [23]   9     |
 |-------------------+-------------------+-------------------|
 | 59    6     4     |[258]  58    7     | 1    [289]  3     |
 | 59    279   2579  | 1     3     256   | 2689  4     268   |
 | 8     1     3     | 24    9     246   | 26    7     5     |
 *-----------------------------------------------------------*


All the 2's in columns 4 & 7 can be excluded, except the ones that have brackets. I'm not sure why the hint didn't indicate that r9c4 would have to be 4, which seems a more obvious move than the one given. Probably the order in which techniques are implemented and it would have already found the box/box interaction and excluded the 8 from r3c8.
Back to top
View user's profile Send private message
Golfgal



Joined: 31 Jul 2006
Posts: 7

PostPosted: Wed Aug 23, 2006 12:23 pm    Post subject: Reply with quote

Tracey,

So obvious when the answer is presented.......Thank You
Back to top
View user's profile Send private message Send e-mail
Display posts from previous:   
Post new topic   Reply to topic    dailysudoku.com Forum Index -> Daily Sudoku 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