The New Sudoku Players' Forum

[spirit_fantasy]

Code: Select all

*-----------*
 |..8|5..|...|
 |.9.|.68|.7.|
 |..1|...|...|
 |---+---+---|
 |.7.|82.|..6|
 |.5.|...|.8.|
 |8..|.4.|.9.|
 |---+---+---|
 |..9|...|1..|
 |.8.|67.|.3.|
 |...|..2|...|
 *-----------*

[gsf]

this puzzle has 199 solutions

[Hud]

It looks like The puzzle is trying to be symmetrical but several clues are missing (3?).

[Guest]

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).

[QBasicMac]

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--


[spirit_fantasy]

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|...|
 *-----------*

[tarek]

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

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

Tackling too many puzzles at the same time..

tarek

[spirit_fantasy]

wt do u mean by multiple solutions?? so you mean this is not a right sudoku? or i still miss sth?

[lunababy_moonchild]

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!

Luna

[QBasicMac]

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.

Mac

[Pat]

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

[QBasicMac]

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.

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.

Mac

[Pat]

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

[gsf]

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..


[Pat]

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