I want present to you Sudoku Solver, created by me today, which find solution for any level of Sudoku in very short time from 20 to 300 seconds,
depends on difficulty level.

This solution prevents from infinite loop. So if solution exists it'll be found.

In this example I used the very hard sudoku and got solution in 2 minutes.

Sudoku Line

XXX7X29X4
4X1X687XX
XXXXXXXX8
6X7XX142X
XXXXXXXXX
X236XX1X5
1XXXXXXXX
XX827X5X1
7X24X6XXX

Line 1: | 8 | 6 | 5 | 7 | 3 | 2 | 9 | 1 | 4 |
Line 2: | 4 | 3 | 1 | 9 | 6 | 8 | 7 | 5 | 2 |
Line 3: | 2 | 7 | 9 | 1 | 4 | 5 | 6 | 3 | 8 |
Line 4: | 6 | 8 | 7 | 5 | 9 | 1 | 4 | 2 | 3 |
Line 5: | 5 | 1 | 4 | 3 | 2 | 7 | 8 | 9 | 6 |
Line 6: | 9 | 2 | 3 | 6 | 8 | 4 | 1 | 7 | 5 |
Line 7: | 1 | 9 | 6 | 8 | 5 | 3 | 2 | 4 | 7 |
Line 8: | 3 | 4 | 8 | 2 | 7 | 9 | 5 | 6 | 1 |
Line 9: | 7 | 5 | 2 | 4 | 1 | 6 | 3 | 8 | 9 |

==> Code in attachment. <==

Thanks everybody (Especially tonkuma) who shown to me drawbacks in the Old Solver.

Leonid Khiger

this is great! spasibo Leonid! can you do the same for chess? a chess-solver?

Had father 3 sons, 2 and dummy1 !

I have made something for chess, already.
But now chess-sql works only as chess-puzzles solver.

Yours Lenny

Sorry guys, but I can't stop.

Now I have optimized Absolute SUDOKU Solver and found solution for same puzzle which I shown to you yesterday in 20 seconds.

Compare to 2 minutes with V1 of ASS this is not so bad, I think.

Lenny

You can try yourself, trying to solve Valentine Sudoku:

Then we'll compare result and time.

Lenny

I want present to Final Solution (SUDOKU Killer).

This one working 60 time faster then Version Two.

Lenny

There is level 3 sudoku, having 2 empty lines:

Sudoku Line

XXXXXXXXX
X7XXX6X3X
X3X72XX4X
7XXXX8XX1
6XX3X7XX5
5X91XXXXX
X8XX91X2X
X916XXX7X
XXXXXXXXX
Line 1: | 9 | 6 | 2 | 8 | 3 | 4 | 1 | 5 | 7 |
Line 2: | 8 | 7 | 4 | 5 | 1 | 6 | 9 | 3 | 2 |
Line 3: | 1 | 3 | 5 | 7 | 2 | 9 | 6 | 4 | 8 |
Line 4: | 7 | 2 | 3 | 9 | 5 | 8 | 4 | 6 | 1 |
Line 5: | 6 | 1 | 8 | 3 | 4 | 7 | 2 | 9 | 5 |
Line 6: | 5 | 4 | 9 | 1 | 6 | 2 | 7 | 8 | 3 |
Line 7: | 3 | 8 | 7 | 4 | 9 | 1 | 5 | 2 | 6 |
Line 8: | 2 | 9 | 1 | 6 | 8 | 5 | 3 | 7 | 4 |
Line 9: | 4 | 5 | 6 | 2 | 7 | 3 | 8 | 1 | 9 |

Our solver spent 11 second to find this single solution.

Now we make simple experiment: we'll change line 4 by remove 1 from source string:

7XXXX8XX1 ==> 7XXXX8XX0

We expect the same single solution, but not.

Because we have 2 empty lines we'll have multiple solutions.

Ok, every solution will shown to you, but how ?

Line 1: ........
Line 1: ........
..................
Line 1: ........
Line 2: ........
Line 2: ........
..................
Line 2: ........ etc.

How combine these lines in complete sudoku solutions ?

For this I created the new termin (column) named Weight.

The weight has to be unique for every single solution.

Weight = 'Line 1:... ' || 'Line 2:... ' ||.... || 'Line 9:... '.

Then I used Group By and Order BY for Weight & Line##.

As Result:

Sudoku Line
XXXXXXXXX
X7XXX6X3X
X3X72XX4X
7XXXX8XXX
6XX3X7XX5
5X91XXXXX
X8XX91X2X
X916XXX7X
XXXXXXXXX
Line 1: | 1 | 6 | 2 | 8 | 3 | 4 | 7 | 5 | 9 |
Line 2: | 9 | 7 | 4 | 5 | 1 | 6 | 8 | 3 | 2 |
Line 3: | 8 | 3 | 5 | 7 | 2 | 9 | 6 | 4 | 1 |
Line 4: | 7 | 1 | 3 | 9 | 5 | 8 | 2 | 6 | 4 |
Line 5: | 6 | 2 | 8 | 3 | 4 | 7 | 1 | 9 | 5 |
Line 6: | 5 | 4 | 9 | 1 | 6 | 2 | 3 | 8 | 7 |
Line 7: | 3 | 8 | 7 | 4 | 9 | 1 | 5 | 2 | 6 |
Line 8: | 2 | 9 | 1 | 6 | 8 | 5 | 4 | 7 | 3 |
Line 9: | 4 | 5 | 6 | 2 | 7 | 3 | 9 | 1 | 8 |

Line 1: | 1 | 6 | 2 | 8 | 3 | 4 | 7 | 5 | 9 |
Line 2: | 9 | 7 | 4 | 5 | 1 | 6 | 8 | 3 | 2 |
Line 3: | 8 | 3 | 5 | 7 | 2 | 9 | 6 | 4 | 1 |
Line 4: | 7 | 1 | 3 | 9 | 5 | 8 | 2 | 6 | 4 |
Line 5: | 6 | 2 | 8 | 3 | 4 | 7 | 9 | 1 | 5 |
Line 6: | 5 | 4 | 9 | 1 | 6 | 2 | 3 | 8 | 7 |
Line 7: | 3 | 8 | 7 | 4 | 9 | 1 | 5 | 2 | 6 |
Line 8: | 2 | 9 | 1 | 6 | 8 | 5 | 4 | 7 | 3 |
Line 9: | 4 | 5 | 6 | 2 | 7 | 3 | 1 | 9 | 8 |

Line 1: | 1 | 6 | 2 | 8 | 3 | 4 | 7 | 5 | 9 |
Line 2: | 9 | 7 | 4 | 5 | 1 | 6 | 8 | 3 | 2 |
Line 3: | 8 | 3 | 5 | 7 | 2 | 9 | 6 | 4 | 1 |
Line 4: | 7 | 2 | 3 | 9 | 5 | 8 | 1 | 6 | 4 |
Line 5: | 6 | 1 | 8 | 3 | 4 | 7 | 2 | 9 | 5 |
Line 6: | 5 | 4 | 9 | 1 | 6 | 2 | 3 | 8 | 7 |
Line 7: | 3 | 8 | 7 | 4 | 9 | 1 | 5 | 2 | 6 |
Line 8: | 2 | 9 | 1 | 6 | 8 | 5 | 4 | 7 | 3 |
Line 9: | 4 | 5 | 6 | 2 | 7 | 3 | 9 | 1 | 8 |

Line 1: | 1 | 6 | 2 | 8 | 3 | 4 | 9 | 5 | 7 |
Line 2: | 9 | 7 | 4 | 5 | 1 | 6 | 2 | 3 | 8 |
Line 3: | 8 | 3 | 5 | 7 | 2 | 9 | 6 | 4 | 1 |
Line 4: | 7 | 1 | 3 | 9 | 5 | 8 | 4 | 6 | 2 |
Line 5: | 6 | 2 | 8 | 3 | 4 | 7 | 1 | 9 | 5 |
Line 6: | 5 | 4 | 9 | 1 | 6 | 2 | 7 | 8 | 3 |
Line 7: | 3 | 8 | 7 | 4 | 9 | 1 | 5 | 2 | 6 |
Line 8: | 2 | 9 | 1 | 6 | 8 | 5 | 3 | 7 | 4 |
Line 9: | 4 | 5 | 6 | 2 | 7 | 3 | 8 | 1 | 9 |

Line 1: | 9 | 6 | 2 | 8 | 3 | 4 | 1 | 5 | 7 |
Line 2: | 8 | 7 | 4 | 5 | 1 | 6 | 2 | 3 | 9 |
Line 3: | 1 | 3 | 5 | 7 | 2 | 9 | 6 | 4 | 8 |
Line 4: | 7 | 1 | 3 | 9 | 5 | 8 | 4 | 6 | 2 |
Line 5: | 6 | 2 | 8 | 3 | 4 | 7 | 9 | 1 | 5 |
Line 6: | 5 | 4 | 9 | 1 | 6 | 2 | 7 | 8 | 3 |
Line 7: | 3 | 8 | 7 | 4 | 9 | 1 | 5 | 2 | 6 |
Line 8: | 2 | 9 | 1 | 6 | 8 | 5 | 3 | 7 | 4 |
Line 9: | 4 | 5 | 6 | 2 | 7 | 3 | 8 | 9 | 1 |

Line 1: | 9 | 6 | 2 | 8 | 3 | 4 | 1 | 5 | 7 |
Line 2: | 8 | 7 | 4 | 5 | 1 | 6 | 9 | 3 | 2 |
Line 3: | 1 | 3 | 5 | 7 | 2 | 9 | 6 | 4 | 8 |
Line 4: | 7 | 2 | 3 | 9 | 5 | 8 | 4 | 6 | 1 |
Line 5: | 6 | 1 | 8 | 3 | 4 | 7 | 2 | 9 | 5 |
Line 6: | 5 | 4 | 9 | 1 | 6 | 2 | 7 | 8 | 3 |
Line 7: | 3 | 8 | 7 | 4 | 9 | 1 | 5 | 2 | 6 |
Line 8: | 2 | 9 | 1 | 6 | 8 | 5 | 3 | 7 | 4 |
Line 9: | 4 | 5 | 6 | 2 | 7 | 3 | 8 | 1 | 9 |

Line 1: | 9 | 6 | 2 | 8 | 3 | 4 | 7 | 5 | 1 |
Line 2: | 8 | 7 | 4 | 5 | 1 | 6 | 9 | 3 | 2 |
Line 3: | 1 | 3 | 5 | 7 | 2 | 9 | 6 | 4 | 8 |
Line 4: | 7 | 1 | 3 | 9 | 5 | 8 | 2 | 6 | 4 |
Line 5: | 6 | 2 | 8 | 3 | 4 | 7 | 1 | 9 | 5 |
Line 6: | 5 | 4 | 9 | 1 | 6 | 2 | 3 | 8 | 7 |
Line 7: | 3 | 8 | 7 | 4 | 9 | 1 | 5 | 2 | 6 |
Line 8: | 2 | 9 | 1 | 6 | 8 | 5 | 4 | 7 | 3 |
Line 9: | 4 | 5 | 6 | 2 | 7 | 3 | 8 | 1 | 9 |

Line 1: | 9 | 6 | 2 | 8 | 3 | 4 | 7 | 5 | 1 |
Line 2: | 8 | 7 | 4 | 5 | 1 | 6 | 9 | 3 | 2 |
Line 3: | 1 | 3 | 5 | 7 | 2 | 9 | 6 | 4 | 8 |
Line 4: | 7 | 2 | 3 | 9 | 5 | 8 | 1 | 6 | 4 |
Line 5: | 6 | 1 | 8 | 3 | 4 | 7 | 2 | 9 | 5 |
Line 6: | 5 | 4 | 9 | 1 | 6 | 2 | 3 | 8 | 7 |
Line 7: | 3 | 8 | 7 | 4 | 9 | 1 | 5 | 2 | 6 |
Line 8: | 2 | 9 | 1 | 6 | 8 | 5 | 4 | 7 | 3 |
Line 9: | 4 | 5 | 6 | 2 | 7 | 3 | 8 | 1 | 9 |

we got 8 different solutions in 1 minute.

Lenny

P.S. Code in an attachment

Leonid, what makes you think dummy1 is one of 3 sons, maybe daughther

You are absolutely righ. Could be daughther, could be twins.

This is old russian story about 1 father and 3 sons.

One of them had exactly the same name with dummy1.

Lenny

I remember about 1 father and 3 sons

I'm not expert in English, but I believe dummy is not the same as durak

I did not say so. But Ivan Durak was smartest guy in russia. Forever.

Dummy1 understood my joke, what about you ?

Lenny

I knew you were referring to that story about father and 3 sons, but maybe I didn't understand your joke.

Bella, what do you want from me ?

I don't fill sorry.
He asked me about chess-solver in DB2.
I have answered to him, how I want. That it.

Lenny

I was just joking with you... Sorry for "flooding" your thread, I'll stop here.

It's Ok. How in Canada translate the word "dummy" to russian ?

Lenny