Sudoku Sudoku


Submit your own Pic! 101 Comments
Play this pic as a Jigsaw
or Sliding Puzzle
Previous / Next
Play sudoku on your site/blog

Choose a number, and place it in the grid above.
  1 2 3 4 5 6 7 8 9
This number is a possibility
Automatically remove Possibilities
Allow incorrect Moves
Clicking the playing grid places the current number
Highlight Current Square
Grey out Used Numbers
Possibilities in Grid Format
Check out the latest post in the Sudoku Forum


Submitted by: uno hu

Indicate which comments you would like to be able to see

Awww, drunk kitty! Good MaeN all!
 |  |
 |  |
whoops forgot to restart the timer after a pause
I guess he fell asleep after a big play with the box
 |  |
If one is to have a discussion about complexity of solving techniques, perhaps non-fc logic needs to be evaluated also. Although the solution I came up with for todays puzzle can be written as an fc, it is somewhat simpler to look at it otherwise. To wit: If h6=1 then both f7 and g7 are 1, More...
 |  |
there is something called simultaneous equations using matrices, then it's so easy u could cry.
 |  |
The 'solution' suggested above can be performed at 43 filled after using 3 sets depth 1 to get there, I think. A pair elimination, a pointing elim, and a pair elim - all focusing on box a2, or thereabouts.(at 27,28,28 filled, respectively).
 |  |
lol - the solution I suggested, I mean - not the one suggested from the higher power.
 |  |
21:21 all depended on where I went looking for my chains...
 |  |
Hi Steve, interesting comment.

1) In a way the best solution for each solver is the one he found by himself : there's no discussing it (but for trying to create an objective complexity measuring tool)!

2) I must insist on a point about fcs : they are more a writing tool than a More...
 |  |
Your argument (at 52 filled, if I understand) is
'If h6=1 then both f7 and g7 are 1, therefor h6 is not 1'.
We could also say
'Whether f6=1 or f7=1, giving g4=1, h6 is not 1'.
'Whether g4=1 or g7=1, giving f6=1, h6 is not 1'.
or... let me stop here. These are (at least) but three ways of reading the same fc :
(f6=1)==(f7=1)--(g7=1)==(g4=1) forbids h6=1.

 |  |
Well you may accept or not that your argument is a fc and prefer your way among the others of telling the story, anyway, it needs examining two sets : {f67=1}=possible ones in col f, and {g47=1}=possible ones in col g. So do you agree to give your argument the weigh 'two sets needed' ?
 |  |
Let's return to my last elimination at 31 filled (after which easy fillings to the end) :

(f6=1)==(h6=1)--(g4=1)==(g7=1) forbids f7=1

You can perfectly read it your mood :
'if f7=1 then both g4 and h6 are 1, so f7 is not 1'.

 |  |
A complete proof for fc-allergic readers :

1) easy fillings to 27 filled
2) locked 8s in gi5 : eliminate def5=8, then easy fillings to 31
3) hidden pair 36 in c17 : eliminate c1=4
4) hidden pair 25 in ab3 : eliminate a3=9
5) colors with 1s : if f7=1 then both g4 and h6 are 1, so More...
 |  |
 |  |
Hi Steve,

your more precisely sketched solution gives it now the same complexity than mine (pair elim=2 sets). So it's a draw ? shake hands !

But I didn't mean at all to maintain that my solution was better ! I just wanted to highlight the role of fcs as a unifying vocabulary allowing a precise definition of the complexity of a proof.
 |  |
 |  |
 |  |
 |  |
Apr. 25, 2007. Easy until the end, then lots of 1, 3, 9 triples.
26/Apr/07 8:10 AM
 |  |
20:09 - Better
16/Nov/07 1:29 PM
 |  |

05/Sep/10 9:59 AM
 |  |
Please Log in to post a comment.

Not a member? Joining is quick and free.
As a member you get heaps of benefits.
Click Here to join.
You can also try the Chatroom (No one chatting right now - why not start something? )
Check out the Sudoku Blog     Subscribe
Or try the Kids Sudokus (4x4 & 6x6)
Printer Friendly versions:
Members Get Goodies!
Become a member and get heaps of stuff, including: stand-alone sudoku game, online solving tools, save your times, smilies and more!
Welcome our latest Members
Brewster from Sydney, NSW
BeautyRose from hongkong
Paulz from Greymouth
Member's Birthdays Today
Deb from Calamvale, Jonjo from Brisbane
Friends currently online
Want to see when your friends are online? Become a member for free.

Network Sites

Melbourne Bars Find the Hidden Bars of Melbourne
Free Crossword Puzzles Play online or print them out. 2 new crosswords daily.
Jigsaw Puzzles Play online jigsaw puzzles for free, with new pictures everyday
Sliding Puzzle Play online with your own photos
Flickr Sudoku Play sudoku with pictures from Flickr
Kakuro Play Kakuro online!
Wordoku Free Wordoku puzzles everyday.
Purely Facts Test your General Knowledge.
Pumpkin Carving Pattern Free halloween pumpkin carving patterns.