• Source 
    1. -- who is the culprit
    2.  
    3. data Member = A | B | C | D | E deriving ( Show, Eq )
    4.  
    5. nxor x y =  ( x && y ) || ( not x && not y )
    6.  
    7. condA ( liar, culp ) = nxor ( liar  /=A ) $ culp /= A
    8. condB ( liar, culp ) = nxor ( liar  /=B ) $ culp == A || culp == C
    9. condC ( liar, culp ) = nxor ( liar  /=C ) $ liar /= B || liar /= D
    10. condD ( liar, culp )= nxor ( liar  /=D ) $ culp /= B && culp /= E
    11. condE ( liar, culp )= nxor ( liar  /=E ) $ culp /= liar
    12.  
    13. cases = [ ( liar, culp ) | 
    14.         liar <- [ A,B,C,D,E ],
    15.         culp  <- [ A,B,C,D,E ] ]
    16.  
    17. conds = [ condA, condB,  condC, condD, condE ]
    18.  
    19. isPossible theCase = all id [ cond theCase | 
    20.     cond <- conds ]
    21.  
    22. main = do
    23.     mapM_ print $ [ theCase | theCase <- cases, isPossible theCase ]
    24.