Need help!!! The hardest puzzle i have ever seen...

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Need help!!! The hardest puzzle i have ever seen...

Postby spirit_fantasy » Fri Mar 31, 2006 4:55 am

Code: Select all
*-----------*
 |..8|5..|...|
 |.9.|.68|.7.|
 |..1|...|...|
 |---+---+---|
 |.7.|82.|..6|
 |.5.|...|.8.|
 |8..|.4.|.9.|
 |---+---+---|
 |..9|...|1..|
 |.8.|67.|.3.|
 |...|..2|...|
 *-----------*
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Re: Need help!!! The hardest puzzle i have ever seen...

Postby gsf » Fri Mar 31, 2006 5:02 am

this puzzle has 199 solutions
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Postby Hud » Fri Mar 31, 2006 4:27 pm

It looks like The puzzle is trying to be symmetrical but several clues are missing (3?).
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Postby Guest » Fri Mar 31, 2006 6:57 pm

One thing I noticed: in the upper left-hand corner, the only possibilities for a 7 are on the left column. So that means that, in the lower left-hand box, a 7 has to go in the right column (specifically, the 3rd row).
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Postby QBasicMac » Fri Mar 31, 2006 11:07 pm

me wrote:One thing I noticed: in the upper left-hand corner, the only possibilities for a 7 are on the left column. So that means that, in the lower left-hand box, a 7 has to go in the right column (specifically, the 3rd row).


Nice observation. Unfortunately, all 199 solutions already have a 7 placed there, so no progress.:(

I guess the original problem is as posted below and the title of this thread should be changed to "Easiest puzzle I ever saw" - LOL

Mac


Code: Select all
--8  5--  ---
-9-  -68  -7-
--1  ---  3--

-7-  82-  --6
-5-  ---  -8-
8--  -46  -9-

--9  ---  1--
-8-  67-  -3-
---  --2  8--
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Postby spirit_fantasy » Sun Apr 23, 2006 3:25 am

oh yes...i really missed a 7 in left bottom box...it should be like this..but i still cannot get it...help!!!

Code: Select all
*-----------*
 |..8|5..|...|
 |.9.|.68|.7.|
 |..1|...|...|
 |---+---+---|
 |.7.|82.|..6|
 |.5.|...|.8.|
 |8..|.4.|.9.|
 |---+---+---|
 |..9|.8.|1.7|
 |.8.|67.|.3.|
 |..7|.52|...|
 *-----------*
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Postby tarek » Sun Apr 23, 2006 8:12 am

Still, multiple solutions...........

No wonder you are in distress........

Tackling too many puzzles at the same time..

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Postby spirit_fantasy » Sun Apr 23, 2006 12:18 pm

wt do u mean by multiple solutions?? so you mean this is not a right sudoku? or i still miss sth?
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Postby lunababy_moonchild » Sun Apr 23, 2006 12:27 pm

spirit_fantasy wrote:wt do u mean by multiple solutions?? so you mean this is not a right sudoku? or i still miss sth?
It means that there is more than one solution to this sudoku and, as such, is considered to be invalid - because it takes guesswork to solve it and you have no way of knowing if the solution you get could be one of the correct ones without checking all of them!

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Postby QBasicMac » Sun Apr 23, 2006 2:41 pm

spirit_fantasy wrote:oh yes...i really missed a 7 in left bottom box...it should be like this..but i still cannot get it...help!!!


The publication editor goofed and left out something. As a result of that goof by the editor, you were stuck with an impossible puzzle. You will never solve the bad puzzle. It has no single solution and thus no logic will lead to any solution. You have to use trial and error over and over again to find all the "solutions". This is a complete waste of time. And so is reporting that you are still having problems. You will have problems until the end of time. Nobody can help you because there is no answer.

Didn't you see my post above? It has the probable actual puzzle that should have been printed. Quit trying to solve your flawed version and instead solve the puzzle I posted. It is valid.

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re: missing clues

Postby Pat » Sun Apr 23, 2006 3:07 pm

QBasicMac wrote:
Code: Select all
 . . 8 | 5 . . | . . .
 . 9 . | . 6 8 | . 7 .
 . . 1 | . . . | 3 . .
-------+-------+------
 . 7 . | 8 2 . | . . 6
 . 5 . | . . . | . 8 .
 8 . . | . 4 6 | . 9 .
-------+-------+------
 . . 9 | . . . | 1 . .
 . 8 . | 6 7 . | . 3 .
 . . . | . . 2 | 8 . .


that's nice, QBasicMac, finding the missing clues
- tell us how you did it!


by the way, 2 clues can be removed from box5,
this one has a single answer [ 24 clues, Very Hard ] -

Code: Select all
 . . 8 | 5 . . | . . .
 . 9 . | . 6 8 | . 7 .
 . . 1 | . . . | 3 . .
-------+-------+------
 . 7 . | . 2 . | . . 6
 . 5 . | . . . | . 8 .
 8 . . | . 4 . | . 9 .
-------+-------+------
 . . 9 | . . . | 1 . .
 . 8 . | 6 7 . | . 3 .
 . . . | . . 2 | 8 . .



~ Pat
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Re: re: missing clues

Postby QBasicMac » Sun Apr 23, 2006 3:39 pm

Pat wrote:that's nice, QBasicMac, finding the missing clues
- tell us how you did it!


It was back on April 1st, so this is from memory:
I build a txt file with 119 lines (the solutions of the puzzle)
I wrote a QBasic program to count occurrences of digits per position
It would identify a position where, for example, there were 95 occurrences of 6 and a few occurrences of the remaining 8 digits. So I would assume a 6 in that position, but only if it was a missing slot as I was shooting for a symmetrical puzzle.

I think I left all original digits as correct, but I might have removed some. The question is what to do to obtain symmetry: drop a suspect digit or use my method above to add a balancing one.

Anyway, The above would reduce the outstanding duplicate solutions from 119 to 119-95. Repeat on the remaining until only one solution remains.

Pat wrote:by the way, 2 clues can be removed from box5,
this one has a single answer -


Good find! That is a case where I should have dropped the original 8 instead of adding a digit. Probably after fixing a flawed puzzle by the add-a-digit technique, I should follow up by removing pairs and testing for single solution. That would have removed the pair you found. I'll add that to my fix-puzzle checklist. Thanks, Pat.

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a Very Hard puzzle, 22 clues (salvaged from mangled puzzle)

Postby Pat » Mon Apr 24, 2006 1:19 pm

i should've looked further!

2 more clues can be removed (the 8s in box19)

thus we have a Very Hard puzzle
with 22 clues -

Code: Select all
 . . . | 5 . . | . . .
 . 9 . | . 6 8 | . 7 .
 . . 1 | . . . | 3 . .
-------+-------+------
 . 7 . | . 2 . | . . 6
 . 5 . | . . . | . 8 .
 8 . . | . 4 . | . 9 .
-------+-------+------
 . . 9 | . . . | 1 . .
 . 8 . | 6 7 . | . 3 .
 . . . | . . 2 | . . .

~ Pat
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Re: a Very Hard puzzle, 22 clues (salvaged from mangled puzz

Postby gsf » Mon Apr 24, 2006 2:14 pm

Pat wrote:i should've looked further!

2 more clues can be removed (the 8s in box19)

there's 8 minimal 22's and 1 23
Code: Select all
...5......9..68.7...1...3...7..2...6.5.....8.8...4..9...9...1...8.67..3......2...
...5......9..68.7...1...3...7..2...6.5.....8.8...46.....9...1...8.67..3......2...
...5......9..68.7...1...3...7..2...6.5.....8.8...46.9...9...1...8.67.........2...
..85......9..68.7...1...3...7..2...6.5.....8.....4..9...9...1.....67..3......28..
..85......9..68.7...1...3...7..2...6.5.....8.....4..9...9...1...8.67..3......2...
..85......9..68.7...1...3...7..2...6.5.....8.....46.....9...1...8.67..3......2...
..85......9..68.7...1...3...7..2...6.5.....8.....46.9...9...1.....67.........28..
..85......9..68.7...1...3...7..2...6.5.....8.....46.9...9...1...8.67.........2...
..85......9..68.7...1...3...7..2...6.5.....8.8...46.....9...1.....67..3......28..
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re: minimal

Postby Pat » Mon Apr 24, 2006 2:32 pm

gsf wrote:there's 8 minimal 22s and 1 23

thanks, gsf - i don't have any software to help me find the redundant clues.


(of course the one i posted retains the symmetry,
and has some chance of being the original puzzle before it got mangled.)


more important when dropping redundant clues,
is the question of the difficulty-level of the resulting puzzle;
i could hope that all those minimal puzzles are still no tougher than a Pappocom Very Hard,
but i'm not going to load them all into a sudbook just to check up on that---


thanks again!
~ Pat
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