The New Sudoku Players' Forum

[Eioru]

Do sudoku solving techniques have this "Dynamic Double Forcing Chains(+)"

All kind of "Forcing Chains" in my record list are :
6..4..5......2......5..1..62..7..4...9.....8...6..9..37..8..2......5......1..3..5 ~4 Forcing X-Chains
..........4..8..5...3..1..8...9..5...9..6..2...1..8..4...3..7...6..2..9...5..7..1 ~31 Forcing Chains
1.......2.3..4..5...6...7.....1.4....8..2..4....5.8.....2...6...4..3..8.7.......1 ~8 Nishio Forcing Chains
5..2..9......7......6..1..46..9..3...8.....4...7..2..18..3..5......4......1..6..9 ~9 Cell Forcing Chains
1.......2.3..4..5...6...7.....1.4....8..2..4....5.8.....2...6...4..3..8.7.......1 ~23 Region Forcing Chains
1.......2.3..4..5...6...7.....1.4....8..2..4....5.8.....2...6...4..3..8.7.......1 ~12 Dynamic Cell Forcing Chains
1.......2.3..4..5...6...7.....1.3....8..6..3....9.4.....7...1...4..5..8.2.......9 ~2 Dynamic Cell Forcing Chains(+)
..1.....2.3..4....5..6..3....4..7..1....8..3.9..2..6.......8..9.7..2..4.2..1..8.. ~36 Dynamic Contration Forcing Chains
1.......2.3..4..5...6...7.....1.4....8..7..4....5.8.....7...6...5..3..8.2.......1 ~19 Dynamic Contration Forcing Chains(+)
1.......2.3..4..5...6...7.....1.3....4..6..8....4.5.....2...9...8..5..4.7.......1 ~4 Dynamic Double Forcing Chains
None ~0 Dynamic Double Forcing Chains(+)
.....1..2.3..2..4.5..6.......6.....7.7..1..3.8.....5..7....5.......3..2...98..6.. ~27 Dynamic Region Forcing Chains
1.......2.3..4..5...6...7.....1.3....8..7..4....4.6.....2...6...5..3..8.9.......1 ~10 Dynamic Region Forcing Chains(+)

[Ocean]

Is there some sort of super fish here??? (...) Very interesting observation. (...)

daj/ron: I'm happy to see the observations and discussions... Hopefully the puzzle set contains some new material for joy and analysis!

Can I ask you
what time did you spend completing a pattern ( find all puzzles rated over 9.0 )
and what program to use finding these super hard puzzles?

Hi Eioru - Glad to see yours and tareks contributions lately.
The X-pattern is not searched exhaustively. Some subsets of the pattern were searched, each search lasting several hours. Useful observation: Puzzles in the X-pattern that satisfy all of the following conditions - 1. All digits in upper band differ (= first seven nonzero digits). 2. All digits in lower band differ (= last seven digits). 3. All digits in left stack differ (= the three left columns). 4. All digits in right stack differ (= the three right columns). 5. Suexrating > 400. - More than 90% of such puzzles were rated 9.0 or above by Explainer (of the about 200 checked). Very effective screening criteria for finding hard puzzles, once it was established.

[JPF]

Useful observation: Puzzles in the X-pattern that satisfy all of the following conditions - 1. All digits in upper band differ (= first seven nonzero digits). 2. All digits in lower band differ (= last seven digits). 3. All digits in left stack differ (= the three left columns). 4. All digits in right stack differ (= the three right columns). 5. Suexrating > 400. - More than 90% of such puzzles were rated 9.0 or above by Explainer (of the about 200 checked). Very effective screening criteria for finding hard puzzles, once it was established.

Thanks Ocean for this clever observation.

I generated 3 X-pattern puzzles randomly.
Two of them are following the rules => ERR 9.4 and 9.0 :

Code: Select all

900000004020060010003000800000109000010040050000203000007000900060010020400000003
900000007020060010003000800000109000010040050000207000007000900050010020400000003


This one has 2 common digits in stacks 1 and 3

Code: Select all

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



singles only. (14 steppers)

JPF

[ronk]

Can anyone point me to publicly available software ... preferably command line rather than GUI ... which generates permuted puzzles from a given?

TIA, Ron

[gsf]

Can anyone point me to publicly available software ... preferably command line rather than GUI ... which generates permuted puzzles from a given?

my solver
if you just want 99 equivalent copies (plus the original first):

Code: Select all

-J99 -qFN -f%v original.dat

and yes I'm almost out of option letters

[claudiarabia]

Code: Select all

 *-----------*
 |1..|...|..2|
 |.3.|.4.|.5.|
 |..6|...|7..|
 |---+---+---|
 |...|1.4|...|
 |.8.|.7.|.4.|
 |...|5.8|...|
 |---+---+---|
 |..7|...|6..|
 |.5.|.3.|.8.|
 |2..|...|..1|
 *-----------*

I'm getting nostalgic to see this ocean-beauty. With this shape I made my first trial to construct a sudoku on my own one year ago - with paper and pencil. I've forgotten how many numbers I had to add till I finally had a valid one. I know you generate this easily with your program. I still stick to SS and SE while combining them in my efforts and having much joy when I finished one.

Cheers

Claudia[/code]

[claudiarabia]

Here is a free online sudoku solver ....BTW, here is the hardest Sudoku I ever found:
{ 0, 0, 2, 0, 9, 0, 1, 0, 7 },
{ 0, 3, 8, 6, 0, 0, 0, 0, 0 },
{ 4, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 0, 5, 0, 0, 0 },
{ 0, 0, 9, 0, 1, 0, 3, 0, 0 },
{ 0, 0, 0, 4, 0, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 0, 0, 0, 0, 4 },
{ 0, 0, 0, 0, 0, 7, 9, 2, 0 },
{ 8, 0, 6, 0, 3, 0, 7, 0, 0 },

Dear Jon

Thank you for this nice 20-cluer (if r9c7 is omitted) SE rated 2.0!

[JPF]

Thank you for this nice 20-cluer (if r9c7 is omitted) SE rated 2.0!

Claudia,
this puzzle is minimal and is rated 8.4 by SE

JPF

[claudiarabia]

Thank you for this nice 20-cluer (if r9c7 is omitted) SE rated 2.0!

Code: Select all

 *-----------*
 |..2|.9.|1.7|
 |.38|6..|...|
 |4..|...|...|
 |---+---+---|
 |...|..5|...|
 |..9|.1.|3..|
 |...|4..|...|
 |---+---+---|
 |...|...|..4|
 |...|..7|92.|
 |8.6|.3.|7..|
 *-----------*

Claudia,
this puzzle is minimal and is rated 8.4 by SE JPF

Thank you,

I would have missed my favorite construction-SE-level otherwise!
But let me give an excuse for this. When I entered the grid in SE manually, I missed the right place for the 4 in row 7. Instead of putting the 4 correctly in r7c9 I put it in r7c8. Checking out validity SE presented me one unique solution - a rare coincidence which let me believe that I typed everything correctly. And now you can delete the 7 in r9. Anyway I checked solvers in the internet which are not able to solve some hard sudokus so I thought Jon had presented a very bad one or just made a joke. So here is the light-version:

Code: Select all

 *-----------*
 |..2|.9.|1.7|
 |.38|6..|...|
 |4..|...|...|
 |---+---+---|
 |...|..5|...|
 |..9|.1.|3..|
 |...|4..|...|
 |---+---+---|
 |...|...|.4.|
 |...|..7|92.|
 |8.6|.3.|7..|
 *-----------*

Sorry
With best wishes

Claudia

[r.e.s.]

So here is the light-version:

Code: Select all

 *-----------*
 |..2|.9.|1.7|
 |.38|6..|...|
 |4..|...|...|
 |---+---+---|
 |...|..5|...|
 |..9|.1.|3..|
 |...|4..|...|
 |---+---+---|
 |...|...|.4.|
 |...|..7|92.|
 |8.6|.3.|7..|
 *-----------*

Hmmm ... it's very "light" on solutions -- it has none.

[claudiarabia]

Hmmm ... it's very "light" on solutions -- it has none.

If you make one mistake, it will become a mistake-chain, a forcing one, I fear. I did not only put Number four in row 7 on the wrong place, but also the Nr 7 in Row 9 wich I placed in c8 instead of c7. I saw then that c7 only contained the 5 as a candidate and decided to eliminate the 7 because I assumed the 7 in r8 to be enough to define. And it worked. That's how I came to the 2.0 solution.

Code: Select all

 *-----------*
 |..2|.9.|1.7|
 |.38|6..|...|
 |4..|...|...|
 |---+---+---|
 |...|..5|...|
 |..9|.1.|3..|
 |...|4..|...|
 |---+---+---|
 |...|...|.4.|
 |...|..7|92.|
 |8.6|.3.|.7.|
 *-----------*

[/quote]

[Eioru]

Are there sudoku puzzles satisfied any of these?
1. 5 x Dynamic Double Forcing Chains(+)
2. 10 x Dynamic Double Forcing Chains
3. 10 x Dynamic Cell Forcing Chains(+)
4. 2 x Jellyfish
5. 5 x Swordfish
the more numbers, the better
These five are rare solving methods.

[maria45]

Hi Eioru,

is this meant as e.g.

1. > 4 Dynamic Double Forcing Chains(+)

[Ocean]

Do sudoku solving techniques have this "Dynamic Double Forcing Chains(+)"

Here is a puzzle where Explainer applies Dynamic Double Forcing Chains (+). The clue pattern is new for this hardness level (Explainer rating 9.7).

Code: Select all

 *-----------*
 |..1|...|2..|
 |.3.|...|.4.|
 |5..|.6.|..7|
 |---+---+---|
 |...|1.8|...|
 |..4|.3.|8..|
 |...|9.4|...|
 |---+---+---|
 |6..|.2.|..3|
 |.7.|...|.5.|
 |..9|...|1..|
 *-----------*

[Eioru]

Here is a puzzle where Explainer applies Dynamic Double Forcing Chains (+). The clue pattern is new for this hardness level (Explainer rating 9.7).

Code: Select all

 *-----------*
 |..1|...|2..|
 |.3.|...|.4.|
 |5..|.6.|..7|
 |---+---+---|
 |...|1.8|...|
 |..4|.3.|8..|
 |...|9.4|...|
 |---+---+---|
 |6..|.2.|..3|
 |.7.|...|.5.|
 |..9|...|1..|
 *-----------*

Thanks Ocean, and I find on this topic's first page
Ocean #5/M21/D21
.....1..2.1..3..4.5..6.......4.....1.7..8..3.2.....9..9....2.......4..7...35..8..
rated 9.4
also has 1xDynamic Double Forcing Chains (+)

and I feel the ranking is Double=>Cell=>Region=>Contration of average difficulty.

is this meant as e.g.
1. > 4 Dynamic Double Forcing Chains(+)

Yes, though I just find 1 Dynamic Double Forcing Chains(+),
so, it can be done from 2 to more.
Other four are also rare to satisfied.

All kind of "Forcing Chains" in my record list are :

I renew it
5 Forcing X-Chains ~ .1....2.......3..45...2..1.2...6..5...7..8....9.3..........48....49....36......2.
31 Forcing Chains ~ ..........4..8..5...3..1..8...9..5...9..6..2...1..8..4...3..7...6..2..9...5..7..1
11 Nishio Forcing Chains ~ ....6......62.13...278.456..61...45.4.......6.52...13..184.672...47.28......8....
23 Region Forcing Chains ~ 1.......2.3..4..5...6...7.....1.4....8..2..4....5.8.....2...6...4..3..8.7.......1
9 Cell Forcing Chains ~ 5..2..9......7......6..1..46..9..3...8.....4...7..2..18..3..5......4......1..6..9
36 Dynamic Contration Forcing Chains ~ ..1.....2.3..4....5..6..3....4..7..1....8..3.9..2..6.......8..9.7..2..4.2..1..8..
27 Dynamic Region Forcing Chains ~ .....1..2.3..2..4.5..6.......6.....7.7..1..3.8.....5..7....5.......3..2...98..6..
14 Dynamic Cell Forcing Chains ~ .....1..2.1..3..4.5..6.......4.....1.7..8..3.6.....8..2....6.......5..7...39..5..
4 Dynamic Double Forcing Chains ~ 1.......2.3..4..5...6...7.....1.3....4..6..8....4.5.....2...9...8..5..4.7.......1
19 Dynamic Contration Forcing Chains(+) ~ 1.......2.3..4..5...6...7.....1.4....8..7..4....5.8.....7...6...5..3..8.2.......1
10 Dynamic Region Forcing Chains(+) ~ 1.......2.3..4..5...6...7.....1.3....8..7..4....4.6.....2...6...5..3..8.9.......1
2 Dynamic Cell Forcing Chains(+) ~ 1.......2.3..4..5...6...7.....1.3....8..6..3....9.4.....7...1...4..5..8.2.......9
1 Dynamic Double Forcing Chains(+) ~ ..1...2...3.....4.5...6...7...1.8.....4.3.8.....9.4...6...2...3.7.....5...9...1..