The NoFish List

Advanced methods and approaches for solving Sudoku puzzles

DCB

Postby Pat » Thu Sep 12, 2013 11:47 am

Pat wrote:
StrmCkr wrote:
my nxn+k fish finder cannot use multiple same base/cover sectors


is this a programming issue ?

yes the puzzle only has 27 houses
but
the eels are very talented, they can re-use houses as necessary

so we have an array of the houses
— a fixed size (usually 27)

each house has a property dcb
(difference Cover-Base)

in the past, we had a 3-way classification of the houses —
  • this house is not used
  • this house is used in the Cover
  • this house is used in the Base
now, a little more complicated — house(*).dcb
  • 0 = this house is not used
  • +1 = this house is used in the Cover
  • +2 = this house is twice in the Cover
  • +3 = this house is thrice in the Cover
  • -1 = this house is used in the Base
  • -2 = this house is twice in the Base

eel.dcb is the sum (adding all houses)
and might be written in uppercase, DCB.
    (this was J-j in my early comment,
    and daj95376 designated it as "k".)

and cell(*).dcb is also the sum
— here adding for all houses to which this cell belongs.
    we then test for cell.dcb < 0
    and for cell.dcb > DCB
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Re: The NoFish List

Postby David P Bird » Thu Sep 12, 2013 2:19 pm

Pat wrote:
    eel.dcb is the sum (adding all houses)
    and might be written in uppercase, DCB.
      (this was J-j in my early comment,
      and daj95376 designated it as "k".)

If memory serves, someone else added up all the weak sets and subtracted all the strong sets used to make a pattern which I believe he called the pattern's "rank". :-)
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