The New Sudoku Players' Forum

[gsf]

least #clues from a fresh 2.5M collection

Code: Select all

# these puzzles solve with hidden singles and box-line claim (type 1)

# 24 clues antidiagonal minimal (VII)

. . 3  . . 9  4 . .
. . .  6 3 .  8 . .
7 . .  . . .  . . .

. 1 .  . . 2  . . .
. 2 .  . 7 6  . . 9
5 . .  8 9 .  . . 6

8 4 .  . . .  3 7 .
. . .  . . .  2 . .
. . .  . 2 7  . . .

# 24 clues diagonal minimal (VII)

. 9 .  . 1 .  . 7 3
. . .  7 . 2  . . 9
3 . .  . 4 .  . . .

. . .  . . .  . 6 .
. . .  . 8 .  4 . 1
1 . 2  . . .  . 8 .

. 3 .  6 . .  . . .
6 . 8  . . .  . . 7
. 5 .  1 . .  2 . .

# 25 clues horizontal minimal (VI)

4 9 .  . . .  2 . .
6 3 .  1 5 .  . . .
. . .  . . .  . 1 9

. . .  . 9 2  . . 5
. . .  . . .  . 4 .
. . .  . 1 5  . . 2

. . .  . . .  . 7 6
5 6 .  7 3 .  . . .
7 8 .  . . .  5 . .

# 25 clues vertical minimal (VI)

. . 2  6 . 4  5 . .
. 8 .  . . .  . 1 .
4 . .  . . .  . . 6

. . .  3 . 7  . . .
. . 4  5 6 9  7 . .
. . 3  . . .  6 . .

. . .  4 . 1  . . .
5 . 7  . . .  8 . 4
6 . .  . . .  . . 5

# 23 clues pi rotational (180 degrees) minimal (V)

. 8 .  . . .  5 . .
4 . 1  . . 9  . 2 .
. . .  4 . .  6 . .

9 6 .  . 3 .  . . .
. . .  . 4 .  . . .
. . .  . 8 .  . 7 2

. . 8  . . 3  . . .
. 1 .  5 . .  7 . 9
. . 9  . . .  . 8 .

# 26 clues diagonal and antidiagonal symmetric minimal (IV)

2 . .  8 . .  . 3 .
. . .  2 . .  6 . 4
. . .  9 5 .  . 7 .

1 7 3  . . .  . . .
. . 8  . . .  5 . .
. . .  . . .  3 4 7

. 8 .  . 1 2  . . .
9 . 6  . . 3  . . .
. 2 .  . . 4  . . 8

# 28 clues horizontal and vertical symmetric minimal (III)

. 5 .  . 7 .  . 9 .
. . .  4 . 8  . . .
. . 2  5 . 3  1 . .

9 . 8  . . .  5 . 7
2 . .  . . .  . . 9
3 . 1  . . .  6 . 8

. . 3  7 . 5  9 . .
. . .  1 . 4  . . .
. 1 .  . 6 .  . 3 .

# 28 clues full rotational (90 180 270 degrees) symmetric minimal (II)

. 8 2  4 . .  . . .
. 9 .  . . .  . 4 5
. . 3  . 1 .  2 . 9

. . .  . 3 .  . . 8
. . 9  8 . 1  6 . .
8 . .  . 6 .  . . .

1 . 5  . 8 .  9 . .
2 4 .  . . .  . 1 .
. . .  . . 6  7 5 .

# 32 clues full dihedral symmetric minimal (I)

3 8 .  5 4 2  . 6 7
4 . .  9 . 7  . . 5
. . .  . . .  . . .

2 9 .  . . .  . 1 4
5 . .  . . .  . . 6
7 1 .  . . .  . 8 2

. . .  . . .  . . .
1 . .  8 . 6  . . 3
8 7 .  2 9 3  . 5 1


and this one with a big run of box-line steps

Code: Select all

# 29 clues horizontal symmetric minimal (VI) 20 consecutive box-line steps

. . 7  . 4 .  9 3 .
3 2 .  . 1 7  4 . .
4 . .  5 . .  . . .

. . .  . . .  3 9 4
. . .  . . 4  . . .
. . .  . . .  7 2 6

6 . .  1 . .  . . .
1 4 .  . 8 9  6 . .
. . 9  . 3 .  2 1 .


[tarek]

Tarek:

1st is invalid
2nd is valid, the stepcount is: N = 8, F = 4, FN = 3, FB = 3, FNB = 2
3rd is invalid. requires FNB. Stepcount FNB = 11

huh
the second can be solved with three rounds of hidden singles

Code: Select all

[1]  N17 [17]=9 [22]=6 [32]=1 [35]=8 [78]=1 [75]=5 [85]=4 [92]=9 [41]=9
         [62]=5 [24]=4 [74]=8 [36]=5 [16]=6 [48]=8 [33]=2 [66]=2
     N18 [18]=4 [38]=3 [49]=5 [43]=6 [55]=9 [67]=4 [63]=8 [81]=6 [82]=8
         [52]=4 [94]=2 [86]=3 [77]=3 [28]=5 [58]=6 [29]=2 [12]=3 [25]=3
     N12 [39]=7 [45]=1 [44]=3 [57]=2 [61]=3 [71]=2 [72]=7 [88]=2 [93]=3
         [98]=7 [69]=1 [53]=7


I also had 3 rounds of hidden singles but the step count was 20,20,9 = 49, the sum of your steps is 47 (+32 clues makes it 79)

The log of my steps are as follows:

Code: Select all

32 Clues & 49 Left

r9c1 value MUST be 5 (Hidden Single in Column 1)
r4c1 value MUST be 9 (Hidden Single in Column 1)
r3c2 value MUST be 1 (Hidden Single in Column 2)
r6c2 value MUST be 5 (Hidden Single in Column 2)
r2c4 value MUST be 4 (Hidden Single in Column 4)
r8c4 value MUST be 7 (Hidden Single in Column 4)
r7c4 value MUST be 8 (Hidden Single in Column 4)
r3c6 value MUST be 5 (Hidden Single in Column 6)
r1c6 value MUST be 6 (Hidden Single in Column 6)
r1c7 value MUST be 9 (Hidden Single in Column 7)
r4c8 value MUST be 8 (Hidden Single in Column 8)
r1c7 value MUST be 9 (Hidden Single in Row 1)
r2c2 value MUST be 6 (Hidden Single in Row 2)
r3c2 value MUST be 1 (Hidden Single in Row 3)
r3c5 value MUST be 8 (Hidden Single in Row 3)
r7c8 value MUST be 1 (Hidden Single in Row 7)
r7c5 value MUST be 5 (Hidden Single in Row 7)
r8c5 value MUST be 4 (Hidden Single in Row 8)
r9c7 value MUST be 8 (Hidden Single in Row 9)
r9c2 value MUST be 9 (Hidden Single in Row 9)
r3c2 value MUST be 1 (Hidden Single in Box 1)
r3c3 value MUST be 2 (Hidden Single in Box 1)
r1c6 value MUST be 6 (Hidden Single in Box 2)
r3c5 value MUST be 8 (Hidden Single in Box 2)
r1c7 value MUST be 9 (Hidden Single in Box 3)
r6c2 value MUST be 5 (Hidden Single in Box 4)
r6c6 value MUST be 2 (Hidden Single in Box 5)
r9c2 value MUST be 9 (Hidden Single in Box 7)
r8c5 value MUST be 4 (Hidden Single in Box 8)
r7c5 value MUST be 5 (Hidden Single in Box 8)
r7c8 value MUST be 1 (Hidden Single in Box 9)
End of Step 1

r8c1 value MUST be 6 (Hidden Single in Column 1)
r5c2 value MUST be 4 (Hidden Single in Column 2)
r8c2 value MUST be 8 (Hidden Single in Column 2)
r9c3 value MUST be 3 (Hidden Single in Column 3)
r6c3 value MUST be 8 (Hidden Single in Column 3)
r4c4 value MUST be 3 (Hidden Single in Column 4)
r5c5 value MUST be 9 (Hidden Single in Column 5)
r8c6 value MUST be 3 (Hidden Single in Column 6)
r3c6 value MUST be 5 (Hidden Single in Column 6)
r1c6 value MUST be 6 (Hidden Single in Column 6)
r7c7 value MUST be 3 (Hidden Single in Column 7)
r5c8 value MUST be 6 (Hidden Single in Column 8)
r4c8 value MUST be 8 (Hidden Single in Column 8)
r3c9 value MUST be 7 (Hidden Single in Column 9)
r1c8 value MUST be 4 (Hidden Single in Row 1)
r3c8 value MUST be 3 (Hidden Single in Row 3)
r4c9 value MUST be 5 (Hidden Single in Row 4)
r4c7 value MUST be 7 (Hidden Single in Row 4)
r5c5 value MUST be 9 (Hidden Single in Row 5)
r6c1 value MUST be 3 (Hidden Single in Row 6)
r6c3 value MUST be 8 (Hidden Single in Row 6)
r8c1 value MUST be 6 (Hidden Single in Row 8)
r8c2 value MUST be 8 (Hidden Single in Row 8)
r1c8 value MUST be 4 (Hidden Single in Box 3)
r5c2 value MUST be 4 (Hidden Single in Box 4)
r6c3 value MUST be 8 (Hidden Single in Box 4)
r6c6 value MUST be 2 (Hidden Single in Box 5)
r5c5 value MUST be 9 (Hidden Single in Box 5)
r4c9 value MUST be 5 (Hidden Single in Box 6)
r5c8 value MUST be 6 (Hidden Single in Box 6)
r8c1 value MUST be 6 (Hidden Single in Box 7)
r8c2 value MUST be 8 (Hidden Single in Box 7)
r8c6 value MUST be 3 (Hidden Single in Box 8)
End of Step 2

r1c2 value MUST be 3 (Hidden Single in Column 2)
r5c2 value MUST be 4 (Hidden Single in Column 2)
r4c3 value MUST be 6 (Hidden Single in Column 3)
r9c4 value MUST be 2 (Hidden Single in Column 4)
r4c5 value MUST be 1 (Hidden Single in Column 5)
r6c6 value MUST be 2 (Hidden Single in Column 6)
r3c8 value MUST be 3 (Hidden Single in Column 8)
r2c8 value MUST be 5 (Hidden Single in Column 8)
r4c9 value MUST be 5 (Hidden Single in Column 9)
r2c8 value MUST be 5 (Hidden Single in Row 2)
r2c8 value MUST be 5 (Hidden Single in Box 3)
End of Step 3

Steps= 202009

tarek

[Ruud]

Wow, I am a bit overwhelmed by the responses!

The majority seems to prefer the original definitions, so we'll stick with those for now. No bulls Eye

fermat: Everybody can submit puzzles. I have a program that can quickly test a puzzle or a collection of puzzles, so just give it your best and we do the rest. I know that ab is often manually tweaking clues to create the best puzzles.

tarek: Your entry does not qualify. Here are the test results:

Code: Select all

24 clues, Symmetry Class I - Full dihedral
*-----------------*
|. . .|4 2 1|. . .|
|. . 9|. . .|5 . .|
|. 3 .|. . .|. 1 .|
|-----+-----+-----|
|6 . .|. 1 .|. . 9|
|2 . .|5 . 8|. . 1|
|4 . .|. 7 .|. . 3|
|-----+-----+-----|
|. 8 .|. . .|. 7 .|
|. . 6|. . .|2 . .|
|. . .|8 6 3|. . .|
*-----------------*
Ulterior (FB) Rating: (invalid)
Other test results:
 F  : (invalid)
 FN : (invalid)
 N  : (invalid)
 FNB: 11 steps

gsf: You're in the money! All your puzzles qualify.

Here are the results:

Code: Select all

24 clues, Symmetry Class VII - Antidiagonal reflection
*-----------------*
|. . 3|. . 9|4 . .|
|. . .|6 3 .|8 . .|
|7 . .|. . .|. . .|
|-----+-----+-----|
|. 1 .|. . 2|. . .|
|. 2 .|. 7 6|. . 9|
|5 . .|8 9 .|. . 6|
|-----+-----+-----|
|8 4 .|. . .|3 7 .|
|. . .|. . .|2 . .|
|. . .|. 2 7|. . .|
*-----------------*
Ulterior (FB) Rating: 9 steps (4 5 1 6 10 13 10 6 2)
Other test results:
 F  : (invalid)
 FN : (invalid)
 N  : (invalid)
 FNB: 8 steps


24 clues, Symmetry Class VII - Diagonal reflection
*-----------------*
|. 9 .|. 1 .|. 7 3|
|. . .|7 . 2|. . 9|
|3 . .|. 4 .|. . .|
|-----+-----+-----|
|. . .|. . .|. 6 .|
|. . .|. 8 .|4 . 1|
|1 . 2|. . .|. 8 .|
|-----+-----+-----|
|. 3 .|6 . .|. . .|
|6 . 8|. . .|. . 7|
|. 5 .|1 . .|2 . .|
*-----------------*
Ulterior (FB) Rating: 12 steps (7 6 4 3 2 1 3 8 5 8 8 2)
Other test results:
 F  : (invalid)
 FN : (invalid)
 N  : (invalid)
 FNB: 8 steps


25 clues, Symmetry Class VI - Horizontal reflection
*-----------------*
|4 9 .|. . .|2 . .|
|6 3 .|1 5 .|. . .|
|. . .|. . .|. 1 9|
|-----+-----+-----|
|. . .|. 9 2|. . 5|
|. . .|. . .|. 4 .|
|. . .|. 1 5|. . 2|
|-----+-----+-----|
|. . .|. . .|. 7 6|
|5 6 .|7 3 .|. . .|
|7 8 .|. . .|5 . .|
*-----------------*
Ulterior (FB) Rating: 13 steps (6 4 5 4 3 3 4 5 5 6 4 5 2)
Other test results:
 F  : (invalid)
 FN : 12 steps
 N  : (invalid)
 FNB: 7 steps


25 clues, Symmetry Class VI - Vertical reflection
*-----------------*
|. . 2|6 . 4|5 . .|
|. 8 .|. . .|. 1 .|
|4 . .|. . .|. . 6|
|-----+-----+-----|
|. . .|3 . 7|. . .|
|. . 4|5 6 9|7 . .|
|. . 3|. . .|6 . .|
|-----+-----+-----|
|. . .|4 . 1|. . .|
|5 . 7|. . .|8 . 4|
|6 . .|. . .|. . 5|
*-----------------*
Ulterior (FB) Rating: 8 steps (9 4 5 9 9 8 10 2 6 3 5 8 4)
Other test results:
 F  : (invalid)
 FN : 13 steps
 N  : (invalid)
 FNB: 7 steps


23 clues, Symmetry Class V - 180-degree rotational
*-----------------*
|. 8 .|. . .|5 . .|
|4 . 1|. . 9|. 2 .|
|. . .|4 . .|6 . .|
|-----+-----+-----|
|9 6 .|. 3 .|. . .|
|. . .|. 4 .|. . .|
|. . .|. 8 .|. 7 2|
|-----+-----+-----|
|. . 8|. . 3|. . .|
|. 1 .|5 . .|7 . 9|
|. . 9|. . .|. 8 .|
*-----------------*
Ulterior (FB) Rating: 13 steps (8 5 5 2 1 4 4 4 4 4 8 7 2)
Other test results:
 F  : (invalid)
 FN : (invalid)
 N  : (invalid)
 FNB: 9 steps


26 clues, Symmetry Class IV - Diagonal and antidiagonal reflection
*-----------------*
|2 . .|8 . .|. 3 .|
|. . .|2 . .|6 . 4|
|. . .|9 5 .|. 7 .|
|-----+-----+-----|
|1 7 3|. . .|. . .|
|. . 8|. . .|5 . .|
|. . .|. . .|3 4 7|
|-----+-----+-----|
|. 8 .|. 1 2|. . .|
|9 . 6|. . 3|. . .|
|. 2 .|. . 4|. . 8|
*-----------------*
Ulterior (FB) Rating: 10 steps (13 3 2 2 1 4 6 12 10 2)
Other test results:
 F  : (invalid)
 FN : (invalid)
 N  : (invalid)
 FNB: 6 steps


28 clues, Symmetry Class III - Horizontal and vertical reflection
*-----------------*
|. 5 .|. 7 .|. 9 .|
|. . .|4 . 8|. . .|
|. . 2|5 . 3|1 . .|
|-----+-----+-----|
|9 . 8|. . .|5 . 7|
|2 . .|. . .|. . 9|
|3 . 1|. . .|6 . 8|
|-----+-----+-----|
|. . 3|7 . 5|9 . .|
|. . .|1 . 4|. . .|
|. 1 .|. 6 .|. 3 .|
*-----------------*
Ulterior (FB) Rating: 10 steps (8 4 4 6 10 7 4 4 4 2 3)
Other test results:
 F  : (invalid)
 FN : 11 steps
 N  : (invalid)
 FNB: 7 steps


28 clues, Symmetry Class II - Full rotational
*-----------------*
|. 8 2|4 . .|. . .|
|. 9 .|. . .|. 4 5|
|. . 3|. 1 .|2 . 9|
|-----+-----+-----|
|. . .|. 3 .|. . 8|
|. . 9|8 . 1|6 . .|
|8 . .|. 6 .|. . .|
|-----+-----+-----|
|1 . 5|. 8 .|9 . .|
|2 4 .|. . .|. 1 .|
|. . .|. . 6|7 5 .|
*-----------------*
Ulterior (FB) Rating: 9 steps (9 3 4 6 8 7 6 6 4)
Other test results:
 F  : (invalid)
 FN : (invalid)
 N  : (invalid)
 FNB: 5 steps


32 clues, Symmetry Class I - Full dihedral
*-----------------*
|3 8 .|5 4 2|. 6 7|
|4 . .|9 . 7|. . 5|
|. . .|. . .|. . .|
|-----+-----+-----|
|2 9 .|. . .|. 1 4|
|5 . .|. . .|. . 6|
|7 1 .|. . .|. 8 2|
|-----+-----+-----|
|. . .|. . .|. . .|
|1 . .|8 . 6|. . 3|
|8 7 .|2 9 3|. 5 1|
*-----------------*
Ulterior (FB) Rating: 10 steps (3 3 1 2 8 10 7 6 7 2)
Other test results:
 F  : (invalid)
 FN : (invalid)
 N  : (invalid)
 FNB: 8 steps


29 clues, Symmetry Class VI - Horizontal reflection
*-----------------*
|. . 7|. 4 .|9 3 .|
|3 2 .|. 1 7|4 . .|
|4 . .|5 . .|. . .|
|-----+-----+-----|
|. . .|. . .|3 9 4|
|. . .|. . 4|. . .|
|. . .|. . .|7 2 6|
|-----+-----+-----|
|6 . .|1 . .|. . .|
|1 4 .|. 8 9|6 . .|
|. . 9|. 3 .|2 1 .|
*-----------------*
Ulterior (FB) Rating: 12 steps (7 2 1 5 3 1 2 4 9 8 5 5)
Other test results:
 F  : (invalid)
 FN : (invalid)
 N  : (invalid)
 FNB: 8 steps

Keep 'em coming!

When I finished my database, I will update the starting post.

Ruud.

[tarek]

Ruud, I think I fixed the problem... One thing remains though which is counting the steps....I tried gsf's 1st puzzle by hand & by the solver & I can't make 10 placements in 2 steps....

this is how it goes...

Code: Select all

r1c4 value MUST be 7 (Hidden Single in Column 4)
r2c9 value MUST be 7 (Hidden Single in Row 2)
r6c8 value MUST be 2 (Hidden Single in Row 6)
r7c3 value MUST be 2 (Hidden Single in Row 7)
End of Step 1

r3c4 value MUST be 2 (Hidden Single in Column 4)
r2c1 value MUST be 2 (Hidden Single in Row 2)
r7c5 value MUST be 6 (Hidden Single in Row 7)
r7c4 value MUST be 9 (Hidden Single in Row 7)
End of Step 2

r1c9 value MUST be 2 (Hidden Single in Column 9) <-- This had to be in step 3 ??
End of Step 3

Could you Post your solver's log for the 1st 3 steps........

[Edit: another invalid enty removed]

tarek

[ab]

I'm struggling to replicate your step counts Ruud. Here's a couple of entrants, I don't know how good they are!

Code: Select all

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

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



[Ruud]

Could you Post your solver's log for the 1st 3 steps

Here is the complete log. It starts with the placement of the clues, and, as I said, detection of locked candidates type 1 is fully integrated.

At the beginning of each step, you will see the hidden singles detected. The step then completes with the placement of these singles and the LB1 effects.

Clue 3 in R1C3
Clue 9 in R1C6
Clue 4 in R1C7
Clue 6 in R2C4
Clue 3 in R2C5
Digit 3 locked in B3R3D3
Digit 3 disabled in B2R3D3
R3C4D3 disabled
R3C5D3 disabled
R3C6D3 disabled
Clue 8 in R2C7
Clue 7 in R3C1
Clue 1 in R4C2
Clue 2 in R4C6
Clue 2 in R5C2
Digit 2 locked in B6R6D2
Digit 2 disabled in B4R6D2
R6C1D2 disabled
R6C2D2 disabled
R6C3D2 disabled
Clue 7 in R5C5
Clue 6 in R5C6
Clue 9 in R5C9
Clue 5 in R6C1
Clue 8 in R6C4
Clue 9 in R6C5
Clue 6 in R6C9
Clue 8 in R7C1
Digit 8 locked in B4C3D8
Digit 8 disabled in B1C3D8
R3C3D8 disabled
Digit 8 locked in B1C2D8
Digit 8 disabled in B7C2D8
R7C2D8 disabled
R8C2D8 disabled
R9C2D8 disabled
Digit 8 disabled in B7C3D8
R7C3D8 disabled
R8C3D8 disabled
R9C3D8 disabled
Clue 4 in R7C2
Clue 3 in R7C7
Clue 7 in R7C8
Digit 7 locked in B3C9D7
Digit 7 disabled in B6C9D7
R4C9D7 disabled
Digit 7 disabled in B9C9D7
R7C9D7 disabled
R8C9D7 disabled
R9C9D7 disabled
Digit 7 locked in B6C7D7
Digit 7 disabled in B9C7D7
R8C7D7 disabled
R9C7D7 disabled
Clue 2 in R8C7
Digit 2 locked in B6C8D2
Digit 2 disabled in B3C8D2
R1C8D2 disabled
R2C8D2 disabled
R3C8D2 disabled
Digit 2 locked in B3C9D2
Digit 2 disabled in B9C9D2
R7C9D2 disabled
R8C9D2 disabled
R9C9D2 disabled
Digit 2 disabled in B9C8D2
R8C8D2 disabled
R9C8D2 disabled
Clue 2 in R9C5
Digit 2 locked in B2C4D2
Digit 2 disabled in B8C4D2
R7C4D2 disabled
R9C4D2 disabled
Digit 2 locked in B7C3D2
Digit 2 disabled in B1C3D2
R2C3D2 disabled
R3C3D2 disabled
Clue 7 in R9C6
Digit 8 locked in B8R8D8
Digit 8 disabled in B9R8D8
R8C8D8 disabled
R8C9D8 disabled
Digit 7 locked in B2R1D7
Digit 7 disabled in B3R1D7
R1C9D7 disabled
Digit 7 locked in B2C4D7
Digit 7 disabled in B8C4D7
R8C4D7 disabled
R9C4D7 disabled

Step 1

Single in R1D7
Single in R2D7
Single in C3D2
Single in R6D2

Place 7 in R1C4
Digit 2 locked in B2R3D2
Digit 2 disabled in B3R3D2
R3C9D2 disabled
Place 7 in R2C9
Digit 2 locked in B3R1D2
Digit 2 disabled in B1R1D2
R1C1D2 disabled
Place 2 in R7C3
Place 2 in R6C8

Step 2

Single in R1D2
Single in C1D2
Single in B2D2
Single in R7D6
Single in R7D9

Place 2 in R1C9
Place 2 in R2C1
Digit 4 locked in B1C3D4
Digit 4 disabled in B4C3D4
R4C3D4 disabled
R5C3D4 disabled
R6C3D4 disabled
Place 2 in R3C4
Place 6 in R7C5
Place 9 in R7C4

Step 3

Single in R6D4

Place 4 in R6C6
Digit 1 locked in B5R5D1
Digit 1 disabled in B6R5D1
R5C7D1 disabled
R5C8D1 disabled
Digit 1 locked in B6C7D1
Digit 1 disabled in B3C7D1
R3C7D1 disabled
Digit 1 disabled in B9C7D1
R9C7D1 disabled
Digit 1 locked in B5C4D1
Digit 1 disabled in B8C4D1
R8C4D1 disabled
R9C4D1 disabled
Digit 3 locked in B5C4D3
Digit 3 disabled in B8C4D3
R8C4D3 disabled
R9C4D3 disabled
Digit 3 locked in B8R8D3
Digit 3 disabled in B7R8D3
R8C1D3 disabled
R8C2D3 disabled
Digit 4 locked in B2R3D4
Digit 4 disabled in B1R3D4
R3C3D4 disabled
Digit 4 locked in B2C5D4
Digit 4 disabled in B5C5D4
R4C5D4 disabled
Digit 4 disabled in B8C5D4
R8C5D4 disabled

Step 4

Single in B1D4
Single in B2D4
Single in C4D1
Single in R6D1
Single in R6D3
Single in C6D3

Place 4 in R2C3
Place 4 in R3C5
Place 1 in R5C4
Digit 3 locked in B5R4D3
Digit 3 disabled in B4R4D3
R4C1D3 disabled
Digit 3 disabled in B6R4D3
R4C8D3 disabled
R4C9D3 disabled
Digit 3 locked in B6R5D3
Digit 3 disabled in B4R5D3
R5C1D3 disabled
Digit 3 locked in B4C2D3
Digit 3 disabled in B7C2D3
R9C2D3 disabled
Digit 3 locked in B6C8D3
Digit 3 disabled in B3C8D3
R3C8D3 disabled
Digit 5 locked in B5R4D5
Digit 5 disabled in B6R4D5
R4C7D5 disabled
R4C8D5 disabled
R4C9D5 disabled
Place 1 in R6C7
Digit 7 locked in B6R4D7
Digit 7 disabled in B4R4D7
R4C3D7 disabled
Place 3 in R6C2
Digit 7 locked in B4C3D7
Digit 7 disabled in B7C3D7
R8C3D7 disabled
Place 3 in R8C6
Digit 8 locked in B8C5D8
Digit 8 disabled in B2C5D8
R1C5D8 disabled
Digit 8 locked in B2R3D8
Digit 8 disabled in B1R3D8
R3C2D8 disabled

Step 5

Single in R1D8
Single in C1D3
Single in C2D7
Single in B2D8
Single in R3D3
Single in C3D7
Single in R4D3
Single in R4D7
Single in R5D3
Single in C5D8

Place 8 in R1C2
Place 3 in R9C1
Place 7 in R8C2
Place 8 in R3C6
Place 3 in R3C9
Digit 1 locked in B3C8D1
Digit 1 disabled in B9C8D1
R8C8D1 disabled
R9C8D1 disabled
Place 7 in R6C3
Place 3 in R4C4
Digit 5 locked in B5C5D5
Digit 5 disabled in B2C5D5
R1C5D5 disabled
Digit 5 locked in B2R2D5
Digit 5 disabled in B1R2D5
R2C2D5 disabled
Digit 5 locked in B1R3D5
Digit 5 disabled in B3R3D5
R3C7D5 disabled
Digit 5 locked in B3C8D5
Digit 5 disabled in B6C8D5
R5C8D5 disabled
Digit 5 locked in B6C7D5
Digit 5 disabled in B9C7D5
R9C7D5 disabled
Digit 5 disabled in B9C8D5
R8C8D5 disabled
R9C8D5 disabled
R3C8D5 disabled
Digit 5 disabled in B3R2D5
R2C8D5 disabled
Digit 5 locked in B2C6D5
Digit 5 disabled in B8C6D5
R7C6D5 disabled
Digit 5 disabled in B8C5D5
R8C5D5 disabled
Place 7 in R4C7
Place 3 in R5C8
Digit 4 locked in B6R4D4
Digit 4 disabled in B4R4D4
R4C1D4 disabled
Digit 8 locked in B6R4D8
Digit 8 disabled in B4R4D8
R4C3D8 disabled
Place 8 in R8C5
Digit 1 locked in B8R7D1
Digit 1 disabled in B9R7D1
R7C9D1 disabled
Digit 1 locked in B8C6D1
Digit 1 disabled in B2C6D1
R2C6D1 disabled
Digit 1 locked in B2R1D1
Digit 1 disabled in B1R1D1
R1C1D1 disabled
Digit 1 locked in B1R3D1
Digit 1 disabled in B3R3D1
R3C8D1 disabled
Digit 1 locked in B1C3D1
Digit 1 disabled in B7C3D1
R8C3D1 disabled
R9C3D1 disabled
Digit 1 locked in B7R8D1
Digit 1 disabled in B9R8D1
R8C9D1 disabled
Digit 1 disabled in B3R1D1
R1C8D1 disabled

Step 6

Single in R1D1
Single in R1D5
Single in C1D1
Single in C1D4
Single in B1D1
Single in R2D1
Single in R2D5
Single in C3D8
Single in R4D5
Single in R5D5
Single in C6D1
Single in R7D5
Single in R9D1

Place 1 in R1C5
Place 5 in R1C8
Digit 6 locked in B3R3D6
Digit 6 disabled in B1R3D6
R3C2D6 disabled
R3C3D6 disabled
Digit 6 locked in B1C1D6
Digit 6 disabled in B4C1D6
R4C1D6 disabled
Digit 6 locked in B4C3D6
Digit 6 disabled in B7C3D6
R8C3D6 disabled
R9C3D6 disabled
Digit 6 disabled in B7C1D6
R8C1D6 disabled
Digit 6 locked in B7R9D6
Digit 6 disabled in B9R9D6
R9C7D6 disabled
Digit 6 locked in B9C8D6
Digit 6 disabled in B3C8D6
R3C8D6 disabled
R9C8D6 disabled
Place 1 in R8C1
Place 4 in R5C1
Place 1 in R3C3
Digit 5 locked in B1C2D5
Digit 5 disabled in B7C2D5
R9C2D5 disabled
Digit 9 locked in B1C2D9
Digit 9 disabled in B7C2D9
R9C2D9 disabled
Digit 9 locked in B7C3D9
Digit 9 disabled in B4C3D9
R4C3D9 disabled
Place 1 in R2C8
Digit 9 locked in B3R3D9
Digit 9 disabled in B1R3D9
R3C2D9 disabled
Place 5 in R2C6
Place 8 in R5C3
Place 5 in R4C5
Place 5 in R5C7
Place 1 in R7C6
Place 5 in R7C9
Place 1 in R9C9
Digit 8 locked in B9C8D8
Digit 8 disabled in B6C8D8
R4C8D8 disabled

Step 7

Single in R1D6
Single in C1D9
Single in B1D5
Single in B1D9
Single in C2D6
Single in R3D6
Single in C3D6
Single in R4D8
Single in R8D6
Single in C8D8

Place 6 in R1C1
Place 9 in R4C1
Place 5 in R3C2
Place 9 in R2C2
Place 6 in R9C2
Place 6 in R3C7
Digit 9 locked in B3C8D9
Digit 9 disabled in B9C8D9
R8C8D9 disabled
Digit 9 locked in B9R9D9
Digit 9 disabled in B7R9D9
R9C3D9 disabled
R9C8D9 disabled
Place 6 in R4C3
Place 8 in R4C9
Digit 4 locked in B6C8D4
Digit 4 disabled in B9C8D4
R8C8D4 disabled
R9C8D4 disabled
Digit 4 locked in B9R8D4
Digit 4 disabled in B8R8D4
R8C4D4 disabled
Place 6 in R8C8
Place 8 in R9C8

Step 8

Single in R3D9
Single in C3D9
Single in R4D4
Single in C4D4
Single in C7D9
Single in R8D4

Place 9 in R3C8
Place 9 in R8C3
Digit 5 locked in B7R9D5
Digit 5 disabled in B8R9D5
R9C4D5 disabled
Place 4 in R4C8
Place 4 in R9C4
Place 9 in R9C7
Place 4 in R8C9

Step 9

Single in C3D5
Single in C4D5

Place 5 in R9C3
Place 5 in R8C4

I hope this is enough...

In the mean time....How would this score ????

Code: Select all

24 clues, Symmetry Class I - Full dihedral
*-----------------*
|. . .|5 2 4|. . .|
|. . 8|. . .|7 . .|
|. 9 .|. . .|. 4 .|
|-----+-----+-----|
|3 . .|. 1 .|. . 5|
|2 . .|8 . 3|. . 4|
|6 . .|. 7 .|. . 9|
|-----+-----+-----|
|. 7 .|. . .|. 1 .|
|. . 5|. . .|2 . .|
|. . .|9 6 1|. . .|
*-----------------*
Ulterior (FB) Rating: (invalid)
Other test results:
 F  : (invalid)
 FN : (invalid)
 N  : (invalid)
 FNB: 8 steps

[Ruud]

I'm struggling to replicate your step counts Ruud. Here's a couple of entrants, I don't know how good they are!

You can check the log that I posted.

Here are your scores:

#1

Code: Select all

25 clues, Symmetry Class V - 180-degree rotational
*-----------------*
|. 3 2|. . .|8 9 .|
|. 6 .|. . .|. . .|
|. . .|. 9 7|. 4 .|
|-----+-----+-----|
|5 . .|2 . 8|. . .|
|. . 9|. 7 .|4 . .|
|. . .|5 . 9|. . 8|
|-----+-----+-----|
|. 7 .|1 6 .|. . .|
|. . .|. . .|. 1 .|
|. 5 8|. . .|3 7 .|
*-----------------*
Ulterior (FB) Rating: 13 steps (6 4 4 6 2 3 2 5 6 4 6 4 4)
Other test results:
 F  : 16 steps
 FN : 9 steps
 N  : (invalid)
 FNB: 6 steps

#2

Code: Select all

26 clues, Symmetry Class VII - Diagonal reflection
*-----------------*
|. 9 5|. 4 .|. . 8|
|1 4 .|. . 6|. . .|
|. . .|. . .|. . .|
|-----+-----+-----|
|5 . .|7 . .|. 3 .|
|. . 4|8 . .|. . 6|
|. . .|3 2 4|. . .|
|-----+-----+-----|
|7 1 .|. 8 .|. . 5|
|. . 3|. . .|. 6 2|
|. . 6|. . 9|. 7 .|
*-----------------*
Ulterior (FB) Rating: (invalid)
Other test results:
 F  : (invalid)
 FN : 9 steps
 N  : (invalid)
 FNB: 6 steps

Ruud.

[gsf]

I also had 3 rounds of hidden singles but the step count was 20,20,9 = 49, the sum of your steps is 47 (+32 clues makes it 79)

Code: Select all

r9c1 value MUST be 5 (Hidden Single in Column 1)


[91]=5 because its a clue
probably an artifact of turning off naked singles
my count of 79 shows a similar problem

with naked singles turned off at some point in some puzzle the solver
may arrive at a position where only naked singles remain
e.g., in tarek example#2 3 rounds of batched hidden singles leaves the
puzzle with 2 naked singles

somehow those remaining naked singles must be accounted for
the (incorrect) way I tweaked my solver basically treated the
remaining naked singles as clues and they weren't reported

in some sense the remaining naked singles belong to the last constraints applied
but it would be strange to label e.g. naked singles as box-line moves

I think this just means that naked singles can be turned off except for
possibly the end step where there is no choice but to report them so
that clues+moves=81
so for this example there is one last step for the remaining naked singles

Code: Select all

     F2  [47]=7 [65]=7


which are not counted against the "no naked singles"

[Ocean]

Interesting new thread, Ruud!

Could you please define the terms 'naked' and 'hidden' singles?

Here is as I would define them:

Naked singles: There is only one candidate left in a cell.
Hidden single: The candidate occurs in only one cell in a unit (row/column/box).

With this definition, for certain candidates both the 'naked' and 'hidden' strategy can be used to place the same candidate.
So I suppose the rule "5. This also excludes naked singles and locked candidates type 2." does not exclude 'naked' singles that at the same time are 'hidden' singles.

with naked singles turned off at some point in some puzzle the solver
may arrive at a position where only naked singles remain
e.g., in tarek example#2 3 rounds of batched hidden singles leaves the
puzzle with 2 naked singles

somehow those remaining naked singles must be accounted for
the (incorrect) way I tweaked my solver basically treated the
remaining naked singles as clues and they weren't reported

in some sense the remaining naked singles belong to the last constraints applied
but it would be strange to label e.g. naked singles as box-line moves

I think this just means that naked singles can be turned off except for
possibly the end step where there is no choice but to report them so
that clues+moves=81
so for this example there is one last step for the remaining naked singles

Code: Select all

     F2  [47]=7 [65]=7


which are not counted against the "no naked singles"

I don't know if I follow your suggestion here... in the end part most singles are both 'naked' and 'hidden', so why is a special treatment necessary?


Also, one question about locked candidates (pointing pairs): Are multiple levels allowed (locked candidates eliminiate candidates in a second box, which in turn allows a second eliminiation not visible before the first. Similar for a third elimiation, made possible by the second.) And how are these eventually 'counted'?

[Ruud]

Interesting new thread, Ruud!

Thanks. I'm glad it is so well received.

Naked singles: There is only one candidate left in a cell.
Hidden single: The candidate occurs in only one cell in a unit (row/column/box).

Correct. These are also known as the N and F constraints.

A cell that satisfies one of more F constraints and the N constraint at the same time is a valid move in this thread. I call this a "Full House" move in SudoCue, because it is the last placement to complete a house.

Ruud.

[gsf]

I don't know if I follow your suggestion here... in the end part most singles are both 'naked' and 'hidden', so why is a special treatment necessary?

right you are
I was thinking about the case where both naked and hidden singles are disabled

[tarek]

I've sorted that problem gsf thanx (my problem was when a sector has no polyvalued cells with only one cell still uncovered as hidden singles)

Ruud, There is still some problems in counting steps...the reason why I'm not sure of.....

could you be using naked singles for your box-line interactions (which shouldn't happen, you can't utilise information from a cell before uncovering it as a hidden single), because as i can see it you can't place 2 in R1C9 in step 2 as R1C1,R3C9 are still unresolved, Placing 2 in R2C1, R3C4 would lead to resolving both cells & then achieving R1C9 placement...

Another issue...The Hidden single - locked candidates - Hidden single chain should take 2 steps rather than 1 IMO

here the start of solution log:

Code: Select all

.
.
.
.
.
Eliminating 7 From r4c9 (Box 3 & Column 9 Box-Line interaction)
Eliminating 8 From r3c3 (Box 4 & Column 3 Box-Line interaction)
Eliminating 8 From r8c8 (Box 8 & Row 8 Box-Line interaction)
Eliminating 8 From r8c9 (Box 8 & Row 8 Box-Line interaction)
r1c4 value MUST be 7 (Hidden Single in Column 4)
r2c9 value MUST be 7 (Hidden Single in Row 2)
r6c8 value MUST be 2 (Hidden Single in Row 6)
r7c3 value MUST be 2 (Hidden Single in Row 7)
End of Step 1 (4 Placements)

Eliminating 7 From r1c9 (Naked Single in Row 1)
Eliminating 2 From r1c8 (Naked Single in Column 8)
Eliminating 2 From r2c8 (Naked Single in Column 8)
Eliminating 2 From r3c8 (Naked Single in Column 8)
Eliminating 2 From r2c3 (Naked Single in Column 3)
Eliminating 2 From r3c3 (Naked Single in Column 3)
r3c4 value MUST be 2 (Hidden Single in Column 4)
r2c1 value MUST be 2 (Hidden Single in Row 2)
r7c5 value MUST be 6 (Hidden Single in Row 7)
r7c4 value MUST be 9 (Hidden Single in Row 7)
End of Step 2 (4 Placements)

Eliminating 4 From r4c3 (Box 1 & Column 3 Box-Line interaction)
Eliminating 4 From r5c3 (Box 1 & Column 3 Box-Line interaction)
Eliminating 4 From r6c3 (Box 1 & Column 3 Box-Line interaction)
Eliminating 2 From r1c1 (Naked Single in Box 1)
Eliminating 2 From r3c9 (Naked Single in Row 3)
Eliminating 9 From r8c4 (Naked Single in Box 8)
Eliminating 9 From r9c4 (Naked Single in Box 8)
Eliminating 6 From r8c5 (Naked Single in Box 8)
r1c9 value MUST be 2 (Hidden Single in Column 9)
r6c6 value MUST be 4 (Hidden Single in Row 6)
End of Step 3 (2 Placements)

Puzzled

tarek

[tarek]

These are aimed towards the higher end...

Code: Select all

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

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

& theis towards the lower end ........

Code: Select all

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

[Ruud]

Tarek:

Your LowStepper sets a new record. It has been added to the list.

Your HighSteppers did not make it to the list. Here are the results:

Code: Select all

24 clues, Symmetry Class IV - Diagonal and antidiagonal reflection
*-----------------*
|. . 8|5 . 6|. . .|
|. . 7|. . .|8 . .|
|1 4 .|9 . .|. 6 .|
|-----+-----+-----|
|4 . 2|. . .|. . 9|
|. . .|. . .|. . .|
|9 . .|. . .|5 . 1|
|-----+-----+-----|
|. 3 .|. . 2|. 7 4|
|. . 6|. . .|1 . .|
|. . .|3 . 8|9 . .|
*-----------------*
Ulterior (FB) Rating: 15 steps (4 3 2 5 3 2 3 3 3 6 7 3 3 5 5)
Other test results:
 F  : 21 steps
 FN : 13 steps
 N  : (invalid)
 FNB: 8 steps

25 clues, Symmetry Class IV - Diagonal and antidiagonal reflection
*-----------------*
|. . .|. 2 4|1 . .|
|. . 5|. . .|9 . .|
|. 3 .|9 . .|. 7 5|
|-----+-----+-----|
|. . 2|. . .|. . 6|
|1 . .|. 9 .|. . 3|
|9 . .|. . .|2 . .|
|-----+-----+-----|
|6 7 .|. . 3|. 1 .|
|. . 3|. . .|6 . .|
|. . 8|7 6 .|. . .|
*-----------------*
Ulterior (FB) Rating: 15 steps (8 4 4 3 2 1 2 6 4 4 2 2 6 5 3)
Other test results:
 F  : (invalid)
 FN : (invalid)
 N  : (invalid)
 FNB: 9 steps

I see the differences in measuring steps. I will come back with an answer, after I've done some tests.

Ruud.

[tarek]

How about another restriction............

All puzzles making the list should be FN invalid (i.e the puzzle NEEDS locked candidates to solve anyway)........I'll try my best to follow this rule

tarek