## What is the hardest sudoku at from 17s to 40s

Everything about Sudoku that doesn't fit in one of the other sections

### What is the hardest sudoku at from 17s to 40s

Now, I'm finding the hardest sudoku at different conditions.
for exemple,
"The hardest sudokus" says these two:

(1)..1..2..3.2..4..1.5..6..........7..1.3..8..2.4..5..6....5..9..2.7.....8.3.....9..
(2)..1.....2.3..4....5..6..3....7..8..1.6..1..3.1..9..8....5..9..4.8..5..7.2..1..9..

(1) is the hardest sudoku at 23's (9.9)
(2) is the hardest sudoku at 25's (9.9)

:?:
so, what is the hardest sudoku at 17's, 18's, ... , 39's, 40's?
Eioru

Posts: 182
Joined: 16 August 2006

Ocean just discovered this 21-clue puzzle with a rating of 10.0:

.....1..2.1..2..3.4..5.......4.....6.7..3..1.8.....9..5....8.......1..7...64..5..

Many would agree this has a great chance to be THE hardest sudoku for now...
udosuk

Posts: 2698
Joined: 17 July 2005

### re: Ocean's tough puzzle (Explainer rating from 9.4 to 10.0)

udosuk wrote:Ocean just discovered this 21-clue puzzle with a rating of 10.0:

.....1..2.1..2..3.4..5.......4.....6.7..3..1.8.....9..5....8.......1..7...64..5..

Many would agree this has a great chance to be THE hardest sudoku for now...

thanks, udosuk,
http://forum.enjoysudoku.com/viewtopic.php?p=33382#p33382

Pat

Posts: 3873
Joined: 18 July 2005

### Sorry I don't understand

Hi every one
I'm new on the forum and also French so I don't well understand your messages

(1) is the hardest sudoku at 23's (9.9)
(2) is the hardest sudoku at 25's (9.9)

That means that you need 23 seconds with a computer to get the answer?
It's seem incredible for me!

Ocean just discovered this 21-clue puzzle with a rating of 10.0:

What is OCEAN????
What is the rating 10:0?

(I never play sudoku : I code generator and solvcer only!!! )
Papy

Posts: 131
Joined: 15 August 2006

### Re: Sorry I don't understand

(1) is the hardest sudoku at 23's (9.9)

This means that the hardest puzzle found with 23 clues is rated 9.9 out of 10 by Sudoku Explainer. (Adress below).

http://diuf.unifr.ch/people/juillera/Sudoku/Sudoku.html

"Ocean" is one of prominent user names here.
fermat

Posts: 105
Joined: 29 March 2006

### Brute force

I don't speak enougth english to well understand: Ocean is a forum user?

I Read the link about Sudoku explainer we don't have (european and american) the same concept about a brute force and a recursive algorythm
A recursive alogo is a logical algo wich use intermediate result and a BF only try the solutions 1 by 1to find the good solution
You need to compute all the solution and test them one by one...
We have two kind of solver: by elimination or by hypothése so a good solvcer (for us) use only elimination or only hypothese.
It's more difficult!

Actually the challenge is to reconize a grid and the same with perutations!
and in fact to determine if the grid have a unique solution WITHOUT solved it!!!
Have you idea on the other side of Ocean (Atlantique)

Papy
Papy

Posts: 131
Joined: 15 August 2006

### Re: Brute force

I don't speak enougth english to well understand: Ocean is a forum user?

We have two kind of solver: by elimination or by hypothése so a good solvcer (for us) use only elimination or only hypothese.
It's more difficult!

Papy

Ocean is: a member, a poster, a user-name.

Sudoku Explainer uses logic and shows it. No guessing.
fermat

Posts: 105
Joined: 29 March 2006

### Explaijer

Thanks for Ocean I find is profile!!!!

but I not agree with
Sudoku Explainer uses logic and shows it. No guessing.

Why ? Because SE use , for example, Nishio and Nishio is 'guessing'
no logic
You try some value look if the resiult is good, go back and try other value!
It's not 'logic' but guessing

It's what I think but it's not necessaty true!
But SE is a good job!
Papy

Posts: 131
Joined: 15 August 2006