Rating puzzles (XY-Wing, XYZ-Wing, Colors, MultiColors etc)

Henk · Last edited by Henk on Sat Feb 11, 2006 1:53 pm; edited 1 time in total

I just implemented XY-Wing and XYZ-Wing in my solver. The problem now is, how difficult are these techniques in comparison to others. I need a good order of difficulty to give usable hints.

I guess most people would say:

XWing
SwordFish
XY-Wing
XYZ-Wing
Colors
MultiColors
Forcing Chains

personally i use colors very often, so my list would look like:

XWing
Colors
MultiColors
SwordFish
XY-Wing
XYZ-Wing
Forcing Chains

How do you rate these techniques?

edit:
My personal list has some logic:

these only need one candidate number to look at:
XWing
Colors
MultiColors
SwordFish

these need more candidate values to look at:
XY-Wing
XYZ-Wing
Forcing Chains
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Ruud · Site Admin

Hi,

the subject of rating solving techniques has been on this forum many times.

Try this approach:

First, try to solve a dozen or so sudokus in the newspaper with just a pencil and an eraser.

Then solve them again, but this time only using an Excel worksheet that maintains candidates for you.

Then solve the same sudokus with your helper program, which automatically updates candidates, has the option to highlight a single digit so you can see the patterns more clearly, may also highlight cells with 2 candidates, ideal for spotting naked pairs, remote pairs, XY-wings and uniqueness/BUG patterns. (and so on...)

Then write down which techniques you think are the most difficult ones.

There is no single answer.

Ruud.
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Henk · Posted: Fri Jan 13, 2006 7:20 pm Post subject:

Ruud:

Thanks, i searched the forum and i found some usefull information. It seems this topic is very personal. My solver now uses this order:

SingleInBox <-easier than Naked Single because no candidates needed
SingleInRow <-also hidden single, but harder to spot
SingleInColumn
Naked Single
Naked Subsets
PointingPair
BoxLineReduction
Hidden Subsets
Remote Pair
XWing
SwordFish/Yellyfish etc
Colors
MultiColors
XYWing
XYZWing
Forcing Chains
Nishio
Guessing

All these techniques are given a basic rating and a extra rating. When a technique is used to solve the puzzle, the basic rating is added to the puzzle rating. Then for every other time this technique is used, a factor of the extra rating is added to the puzzle rating. This gives a rating witch is higher when more different techniques must be used.

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Ruud · Site Admin

You could put the lowest category up front, the last empty cell in a row/column or box. These should not deserve any points, but depending on the way you implement your solver, they would be interpreted both as naked and hidden singles, and earn more points than they're worth...

Make some room for uniqueness tests. They're more common than you think. In my database of 400.000 sudokus, there are around 3.000 that can be solved with one or more uniqueness tests and no guessing.

And these test are relatively easy to do by a human solver.

Ruud.
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