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From: "B. Pym" <Nobody447095@here-nor-there.org>
Newsgroups: comp.lang.lisp
Subject: Zebra puzzle
Date: Tue, 6 Aug 2024 03:19:32 -0000 (UTC)
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Rosetta: Zebra puzzle

> There are five houses.
> The English man lives in the red house.
> The Swede has a dog.
> The Dane drinks tea.
> The green house is immediately to the left of the white house.
> They drink coffee in the green house.
> The man who smokes Pall Mall has birds.
> In the yellow house they smoke Dunhill.
> In the middle house they drink milk.
> The Norwegian lives in the first house.
> The man who smokes Blend lives in the house next to the house with cats.
> In a house next to the house where they have a horse, they smoke Dunhill.
> The man who smokes Blue Master drinks beer.
> The German smokes Prince.
> The Norwegian lives next to the blue house.
> They drink water in a house next to the house where they smoke Blend. 
> 
> 
> The question is, who owns the zebra? 
> 
> Additionally, list the solution for all the houses.
> Optionally, show the solution is unique.


newLISP


;; Iterate over all permutations of a list, and
;; call a function on each.
(define (permute permute.seq permute.func (permute.built '()))
  (if (null? permute.seq)
    (permute.func permute.built)
    (let (seq (copy permute.seq))
      (dotimes (i (length seq))
        (unless (zero? i) (rotate seq -1))
        (permute
          (rest seq)
          permute.func
          (cons (first seq) permute.built))))))

(define (same-house obj0 lst0  obj1 lst1)
  (= (find obj0 lst0) (find obj1 lst1)))

(define (distance obj0 lst0  obj1 lst1)
  (- (find obj1 lst1) (find obj0 lst0)))

(define (next-to) (= 1 (abs (apply distance (args)))))

(permute '(danish english german norwegian swedish)
  (fn (men)
    (if (= 'norwegian (men 0))
      (permute '(beer coffee milk tea water)
        (fn (drinks)
        (if (and (= 'milk (drinks 2))
                 (same-house 'danish men 'tea drinks))
      (permute '(blue green red white yellow)
        (fn (colors)
          (if (and (= 1 (distance 'green colors 'white colors))
                 (same-house 'english men 'red colors)
                 (same-house 'coffee drinks 'green colors)
                 (next-to 'norwegian men 'blue colors))
      (permute '(blend blue-master dunhill pall-mall prince)
        (fn (smokes)
          (if (and (same-house 'german men 'prince smokes)
                   (same-house 'dunhill smokes 'yellow colors)
                   (same-house 'blue-master smokes 'beer drinks)
                   (next-to 'water drinks  'blend smokes))
      (permute '(birds cats dog horse zebra)
        (fn (pets)
          (if (and (same-house 'swedish men 'dog pets)
                   (same-house 'pall-mall smokes 'birds pets)
                   (next-to 'cats pets  'blend smokes)
                   (next-to 'horse pets 'dunhill smokes)) 
            (println (transpose (list men drinks colors smokes pets)))
              )))))))))))))))


((norwegian water yellow dunhill cats)
 (danish tea blue blend horse)
 (english milk red pall-mall birds)
 (german coffee green prince zebra)
 (swedish beer white blue-master dog))