## Stuck - a week without any progress

Post the puzzle or solving technique that's causing you trouble and someone will help

### Stuck - a week without any progress

Do I have to use try&error here?

sorry but i messed with printing with pencil marks so I'll print without them

_1_*__7*__4
54_*___*___
_72*_8_*_13

___*__8*___
_94*___*26_
___*7__*___

48_*_7_*93_
___*___*___
3__*8__*_7_
Drunkg

Posts: 2
Joined: 28 December 2005

Hi Drunkg,

Simple Sudoku reports that the puzzle is invalid, because
it has numerous solutions (too many to count).

Code: Select all
` *-----------* |.1.|..7|..4| |54.|...|...| |.72|.8.|.13| |---+---+---| |...|..8|...| |.94|...|26.| |...|7..|...| |---+---+---| |48.|.7.|93.| |...|...|...| |3..|8..|.7.| *-----------*  *--------------------------------------------------------------------------------------* | 689      1        3689     | 23569    23569    7        | 568      2589     4        | | 5        4        3689     | 12369    12369    12369    | 678      289      26789    | | 69       7        2        | 4569     8        4569     | 56       1        3        | |----------------------------+----------------------------+----------------------------| | 1267     2356     13567    | 1234569  1234569  8        | 13457    459      1579     | | 178      9        4        | 135      135      135      | 2        6        1578     | | 1268     2356     13568    | 7        1234569  1234569  | 13458    4589     1589     | |----------------------------+----------------------------+----------------------------| | 4        8        156      | 1256     7        1256     | 9        3        1256     | | 12679    256      15679    | 1234569  1234569  1234569  | 14568    2458     12568    | | 3        256      1569     | 8        124569   124569   | 1456     7        1256     | *--------------------------------------------------------------------------------------*`
Nick67

Posts: 113
Joined: 24 August 2007

Nick67 wrote:it has numerous solutions (too many to count).

"Numerous" True! "Too many to count" by that program, but my own QBasic program
http://www.network54.com/Forum/178387/message/1132625620/
reports that there are 21,958 solutions. (and produced a 16500KB txt file with proof those are the only 21,958 solutions).

Here are a couple

613927854548631729972485613137268495894513267256794381485176932769352148321849576

613927854548136729972584613257468391894315267136792485485671932769253148321849576

Therefore, I wonder why Drunkg didn't solve the puzzle. Almost any guess is correct. LOL!

Mac
QBasicMac

Posts: 441
Joined: 13 July 2005

Where did you get this puzzle?

My best guess is that there should be a clue in r8c8 and in r8c9...

Can you double check the clues?

Update: trying to find a unique combination for r8c8 and r8c9 in all the solutions lead me to nowhere... So if you are missing clues then you are missing other clues then r8c8 and r8c9 aswell...
Animator

Posts: 469
Joined: 08 April 2005

Thank you guys! I feel much relief knowing this one can't be solved.

The reason I didn't find any of the 20K solutions is becauise I never guess a solution, I only use logical methods.

I took this sudoku from the most popular newspaper in israel. I'm going to court with these bustards!!! ruind my week!
Drunkg

Posts: 2
Joined: 28 December 2005

Animator wrote:you are missing other clues then r8c8 and r8c9

First off, Drunkq, we are glad you are happy now. Probably the editor thought "what's a few digits more or less?" LOL.

Animator:

What a lot of fun you introduced me to: trying to find missing clues! Thanks!

I got about as far as you, I guess. I determined the following (cell 71 and 72 values versus count of occurrences)
Code: Select all
` 2  1   381 2  5   329 2  6   233 2  8   977 4  2  1162 4  5  1709 4  6  1537 4  8  1157 5  1  1248 5  2   737 5  6  1359 5  8  1679 8  1   934 8  2  2535 8  5  3493 8  6  2488`

Then I got frustrated because the puzzle is now nice and symmetric so there is no hint of where the next clue should be. I guess we could put it in the center or else conclude two more symmetric clues were lost.

I might give up here, but if you figure it out please post your technique.

Mac
QBasicMac

Posts: 441
Joined: 13 July 2005

DrunkG: What's the name of the newspaper? And/or is it listed at http://www.sudoku.com/solutions.php ?

QBasicMac:

I'm using the same technique as you...

2 missing clues (r8c8, r8c9): no combination that occurs only once.
3 missing clues (r5c5, r8c8, r8c9): no combination that occurs only once.
4 missing clues (?, ?, r8c8, r8c9): 22 unique combinations. (list included)
5 missing clues (?, ?, r5c5, r8c8, r8c9): 199 unique combinations.
6 missing clues (?, ?, ?, ?, r8c8, r8c9): 15850 unique combinations.

So the bottom line is: we will never know what the missing clues are... (if they are indeed missing)

Here's the list of 4 missing clues: [COMPLEX] is used to indicate that complex logic is required to solve them...

Code: Select all
`r1c4 = 2, r9c6 = 5, r8c8 = 8, r8c9 = 1 [COMPLEX]r1c5 = 9, r9c5 = 6, r8c8 = 2, r8c9 = 5 [COMPLEX]r2c4 = 3, r8c6 = 2, r8c8 = 5, r8c9 = 1 [COMPLEX]r2c4 = 6, r8c6 = 3, r8c8 = 4, r8c9 = 8r2c4 = 6, r8c6 = 5, r8c8 = 4, r8c9 = 8 [COMPLEX]r2c4 = 6, r8c6 = 5, r8c8 = 8, r8c9 = 1 [COMPLEX]r2c4 = 9, r8c6 = 6, r8c8 = 2, r8c9 = 1r2c5 = 9, r8c5 = 1, r8c8 = 5, r8c9 = 2r2c5 = 9, r8c5 = 6, r8c8 = 4, r8c9 = 2r2c5 = 9, r8c5 = 6, r8c8 = 4, r8c9 = 5 [COMPLEX]r2c5 = 9, r8c5 = 6, r8c8 = 5, r8c9 = 1r2c5 = 9, r8c5 = 6, r8c8 = 5, r8c9 = 8r2c6 = 6, r8c4 = 5, r8c8 = 8, r8c9 = 1r2c6 = 9, r8c4 = 1, r8c8 = 5, r8c9 = 2r2c6 = 9, r8c4 = 2, r8c8 = 5, r8c9 = 1r2c6 = 9, r8c4 = 3, r8c8 = 2, r8c9 = 6r2c6 = 9, r8c4 = 6, r8c8 = 2, r8c9 = 8r2c6 = 9, r8c4 = 6, r8c8 = 4, r8c9 = 2r2c6 = 9, r8c4 = 6, r8c8 = 4, r8c9 = 5r3c6 = 5, r7c4 = 2, r8c8 = 4, r8c9 = 8r3c6 = 6, r7c4 = 2, r8c8 = 2, r8c9 = 1r3c6 = 6, r7c4 = 2, r8c8 = 2, r8c9 = 5`
Animator

Posts: 469
Joined: 08 April 2005

Animator wrote:So the bottom line is: we will never know what the missing clues are... (if they are indeed missing)

> If they are indeed missing

Yep. Could just be a bad puzzle or miscopy (clue 8 is actually 6 somewhere, etc.)

I suspect copy error.

End of interest (unless DrunkG comes up with the source)