Here's one approach:
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EMPTY=: i.0 4
isKnave=: 1 0,2+,
isKnight=:1 1,2+,
isSame=: 1,2+,
isDiff=: 0,2+,
num=: _1+>./@,
enum=: 2 #:@i.@^ num
solve=: enum #~ [: */ ] =/@:{"1/ 0,.1,.enum
Example use:
solve (0 isSame 2 3),(1 isKnight 2),(0 isKnight 1),EMPTY
0 0 0 1
1 1 1 1
This result means that there are two solutions for this example. One
solution is that all four people are knights, the other solution is
that 0, 1 and 2 are knaves while 3 is a knight.
People are identified by index numbers, answers are represented as bit
indices (for each index: 0 if the person would be a knave, 1 if they
would be a knight).
The left argument to the isFoo verbs is the person making the
statement, the right argument is the person (or pair) being critiqued.
--
Raul
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