The New Sudoku Players' Forum

[urhegyi]

Code: Select all

#2//B4/H16
........32......17..5...........6...6.935.....5.1.89..7...8.....8.9......214.....
....71..2...5...........7......5....4.86..9...7.42..8....18..4.9....5618....6....

solution:

Hidden Text: Show

Code: Select all

........32......17..5...........6...6.935.....5.1.89..7...8.....8.9......214..... ED=9.2/1.2/1.2 <- Solved.
....71..2...5...........7......5....4.86..9...7.42..8....18..4.9....5618....6.... ED=7.1/1.2/1.2 <- Solved.
ED=9.2/1.2/1.2
974612853238549617165873492842796135619354278357128946793281564486935721521467389
564371892721598436389246751293857164458613927176429385637182549942735618815964273


[m_b_metcalf]

Code: Select all

 Full solution at iteration 3 puzzle 1

 9 7 4 6 1 2 8 5 3                       
 2 3 8 5 4 9 6 1 7                       
 1 6 5 8 7 3 4 9 2                       
 8 4 2 7 9 6 1 3 5                       
 6 1 9 3 5 4 2 7 8                       
 3 5 7 1 2 8 9 4 6                       
 7 9 3 2 8 1 5 6 4 3 7 1 8 9 2           
 4 8 6 9 3 5 7 2 1 5 9 8 4 3 6           
 5 2 1 4 6 7 3 8 9 2 4 6 7 5 1           
             2 9 3 8 5 7 1 6 4           
             4 5 8 6 1 3 9 2 7           
             1 7 6 4 2 9 3 8 5           
             6 3 7 1 8 2 5 4 9           
             9 4 2 7 3 5 6 1 8           
             8 1 5 9 6 4 2 7 3 
         
 Time:      0.08s

... and one with fewer clues (39):

Code: Select all

9...12..3......6...65...4..8...9.1.....3.4...3...2......3...........5...5........
......8.....5..4.6...2....12..8......5.....2.1....93...........94..3.6.....96.27.

Mike

[m_b_metcalf]

Couldn't resist:

Code: Select all

 . . 1 6 . 8 9 5 .
 9 . 2 . . 1 3 . .
 . . . . . . . 6 .
 . 4 3 . . . . 7 .
 . . . . . . . . .
 . . . . . . . . .
 . . . . . . . . . . . . . . .
 . . . . . . . . . 1 . . . . .
 . . . . . . . . . 4 7 9 . . .
             . 1 . . . . 9 . 8
             6 7 8 . . . . 3 2
             . . 9 . . . . 1 7
             . . . . 1 5 . . .
             . . . . . 2 . . .
             . . . . 3 . . . .  X sensai
           
 Number of clues 32, very hard.

..16.895.9.2..13.........6..43....7..............................................
............1........479....1....9.8678....32..9....17....15........2.......3....

[m_b_metcalf]

Inspired by ruud:

Code: Select all

 . . . . . . . . 2
 . 3 . . . . . 9 .
 . . . . . 3 . . .
 . . . . . . . 8 .
 . . . . . 5 . . .
 . . . . . 6 . . .
 . . . 9 . . . . . . . . . . 9
 . . . 2 7 . . . . . . . . 1 .
 . . 6 . . . . . . . . 5 . . .
             . . . . . . . 6 .
             . . . . . 7 . . .
             . . . . . 4 . . .
             . . . 1 . . . . .
             . . . 9 2 . . . .
             . . 4 . . . . . 8     X sensai, 22 clues, not hard.
           

........2.3.....9......3..........8......5........6......9........27......6......
........9.......1......5..........6......7........4......1........92......4.....8

Mike

[Hajime]

X sensei-1

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. . . 8 . . . . 3               
. 7 . . 6 5 . . 2               
. . . . . . . 5 .               
. . . . 1 . . . .               
6 . . 4 . . . . .               
. . . . . 6 3 . .               
. . . 2 . . . . . . 4 . . . 5   
. . . . 7 1 . . . 1 5 . . . .   
1 . . . 4 . . . . . . 8 . . .   
            . . 3 7 . . . . .   
            . . . . . 3 . . 8   
            . . . . 8 . . . .   
            . 1 . . . . . . .   
            4 . . 3 7 . . 6 .   
            3 . . . . 9 . . .   
                               
#2/X/B4/H16
...8....3.7..65..2.......5.....1....6..4..........63.....2.........71...1...4....
....4...5...15.........8.....37..........3..8....8.....1.......4..37..6.3....9...


Rotation symmetric and very hard

[m_b_metcalf]

Code: Select all

 Full solution at iteration 4 puzzle 1

 4 6 5 8 9 2 1 7 3
 3 7 9 1 6 5 4 8 2
 2 8 1 7 3 4 6 5 9
 8 4 3 9 1 7 5 2 6
 6 5 7 4 2 3 9 1 8
 9 1 2 5 8 6 3 4 7
 7 3 4 2 5 9 8 6 1 9 4 7 2 3 5
 5 9 8 6 7 1 2 3 4 1 5 6 9 8 7
 1 2 6 3 4 8 7 9 5 2 3 8 1 4 6
             5 8 3 7 1 4 6 9 2
             6 4 2 5 9 3 7 1 8
             1 7 9 6 8 2 3 5 4
             9 1 7 8 6 5 4 2 3
             4 2 8 3 7 1 5 6 9
             3 5 6 4 2 9 8 7 1

 Time:  0.28s

I estimate SE ~ 9.

Mike

[Hajime]

Code: Select all

 Time:  0.28s

I estimate SE ~ 9.
Mike

That 0.28s is probably using BruteForce/Backtrack? I do that in 0.057s including check for unique solution.
To test with "all possible logical methods" the time used is 15.236 seconds

[m_b_metcalf]

Backtracking is not required for this puzzle.

BTW, r8c6, r8c10 and r9c1 are separately redundant; either the first or both of the last two can be removed.

Regards,

Mike

[Hajime]

Backtracking is not required for this puzzle.

BTW, r8c6, r8c10 and r9c1 are separately redundant; either the first or both of the last two can be removed.

Regards,

Mike

Removing clues will destroy the symmetry.
4 iterations of what? Which methods do you include?

[m_b_metcalf]

Removing clues will destroy the symmetry.

Ah, yes.

4 iterations of what? Which methods do you include?

Of my program, using standard logic up to SE5.0 and then a candidate-elimination-by-contradiction technique of my own.

Regards,

Mike

[Hajime]

Of my program, using standard logic up to SE5.0 and then a candidate-elimination-by-contradiction technique of my own.

Ah ok, your candidate-elimination-by-contradiction technique looks very much like my Forcing Net, which is T&E(1) I think.
If only basic techniques and Forcing Net is just, the time needed drops to 2.5 seconds, and when all the screen output is off, it drops further to 0.5 seconds.