BUG-lite

Report new features you like us to add to SudoCue
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rep'nA
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Posts: 49
Joined: Fri Jan 19, 2007 11:37 am
Location: Union City, California

BUG-lite

Post by rep'nA »

Today's (Jan. 30) One-Tricky Pony lives up to its name quite admirably today. After singles and a few locked candidates, we arrive at the following grid:

Code: Select all

.------------------.------------------.------------------.
| 8     147   2    | 457   6     9    | 345   13    345  |
| 59*   14    59*  | 3     248   12   | 7     6     48   |
| 3     147   6    | 24578 248   125  | 245   128   9    |
:------------------+------------------+------------------:
| 57    26    8    | 1     239   235  | 34    79    346  |
| 4     9     3    | 6     7     8    | 1     5     2    |
| 157-  26    15*  | 25    239   4    | 8     79    36   |
:------------------+------------------+------------------:
| 2     5     7    | 48    348   6    | 9     348   1    |
| 6     38    4    | 9     1     7    | 235   238   358  |
| 19*   38    19*  | 248   5     23   | 6     2348  7    |
'------------------'------------------'------------------' 
where a BUG-lite implies r6c1 = 7 and the rest is singles. Without this observation, SudoCue uses a skyscraper, followed by a Medusa wrap to finish it off. As long as one accepts uniqueness techniques, the first solution is far more elegant and significantly easier to find.

My wish: Add BUG-lite to the solving techniques.

And as every one of my wishes seems to come with a dream:

My dream: Add RW's Hidden BUG, Reverse BUG and Reverse BUG-lite, if only to see if they really show up.
"Obviousness is always the enemy to correctness."-Bertrand Russell
Ruud
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Joined: Fri Dec 30, 2005 10:21 pm

Post by Ruud »

With these additions, I have the following list of "want to have" techniques:

- ALS-XY-Wing rule
- ALS embedded in AIC
- Franken- and mutant fish
- BUG-Lite
- Almost Locked Candidates
- Hidden BUG
- Reverse BUG
- Reverse BUG-Lite

And finally an "exhaustive search" tool to find all alternative moves in the current candidate grid.

So much to do ... so little time ... :roll:

Ruud
“If the human brain were so simple that we could understand it, we would be so simple that we couldn't.” - Emerson M Pugh
rep'nA
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Hooked
Posts: 49
Joined: Fri Jan 19, 2007 11:37 am
Location: Union City, California

Post by rep'nA »

Ruud wrote:With these additions, I have the following list of "want to have" techniques:

- ALS-XY-Wing rule
- ALS embedded in AIC
- Franken- and mutant fish
- BUG-Lite
- Almost Locked Candidates
- Hidden BUG
- Reverse BUG
- Reverse BUG-Lite

And finally an "exhaustive search" tool to find all alternative moves in the current candidate grid.

So much to do ... so little time ... :roll:

Ruud
Since at least half of those are on my wish/dream list, I think now would be an appropriate time for a thank you. Ruud, you have the rare ability of being an expert designer as well as an expert expositor. You have continued to develop a tool that gives countless hours of joy to us ("too many," says my wife) when most Sudoku designers have given up on improving their solvers. We make suggestions to you because if it takes you a year to program them, that would still be about 10 years faster than it would take us to learn how to program and figure out how to make a solver that ran half as smoothly as yours. So on behalf of everyone:
Everyone wrote:Thank you. Thank you. Thank you.
"Obviousness is always the enemy to correctness."-Bertrand Russell
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