Monday, February 20, 2006

unsolvable sudoku

for you sudoku fans out there, this puzzle can't be solved without using 'Ariadne's Thread' - which basically means that you have to guess at some point. it can be done, but not with pure 'logic.' with the "Allow guess-and-check" option enabled, the sudoku solver will find the solution.

frankly, I was disappointed to find that I had to guess. in my opinion, the sudoku creation people shouldn't use puzzles that require guessing.

_ 5 _ _ 2 _ 8 _ 6
_ _ _ _ _ 6 _ _ 3
_ 6 _ _ 1 3 2 _ _

-------------------
_ 7 _ _ _ _ 9 6 _
4 _ _ _ _ _ _ _ 1
_ 1 6 _ _ _ _ 3 _
-------------------

_ _ 7 2 3 _ _ 8 _
6 _ _ 7 _ _ _ _ _
2 _ 4 _ 9 _ _ 7 _


if you don't believe me, try running it through the sudoku solver.

note: here's the string for the solver (make it all one line):
_5__2_8_6+_____6__3+_6__132__+_7____96_+4____
___1+_16____3_+__723__8_+6__7_____+2_4_9__7_

update: a generous modder has provided the solution for anyone who wants it. those 133t modders just love to teach :P

5 comments:

CLuis said...

1 5 3 | 4 2 7 | 8 9 6
7 4 2 | 9 8 6 | 5 1 3
8 6 9 | 5 1 3 | 2 4 7
---------------------
3 7 5 | 1 4 2 | 9 6 8
4 2 8 | 3 6 9 | 7 5 1
9 1 6 | 8 7 5 | 4 3 2
---------------------
5 9 7 | 2 3 1 | 6 8 4
6 8 1 | 7 5 4 | 3 2 9
2 3 4 | 6 9 8 | 1 7 5

THE SCRIBE said...

I look at that and say,"why would I even wanna try and solve that." And there are others who look at it and solve it...

leeo said...

753 429 816
142 876 593
968 513 247

375 142 968
429 638 751
816 957 432

537 264 189
691 785 324
284 391 675

With the previous poster's comment, this proves the puzzle as presented has more than one solution, and is thus under-determined.

Anonymous said...

No, im sorry i have to dissapoint you the puzzle has only one solution and its the one from CLuis

Anonymous said...

Try the www.sodukuwiki.org site and you will see that there is a logic solution.

H.Breukink