Scheme altering tree values

Asked Apr 24 '18 at 18:12

Active Apr 24 '18 at 18:26

Viewed 20 times

I receive a tree and suppose to output the same tree with the values negated: 1 becomes -1, -2 becomes 2, #t becomes #f and the opposite way.

The tree is flexible - each can have multiple sons, one or none. I'm not allowed to add user-defined helper procedures. However, I can use built-in (primitive) procedures: length, equal?, append, foldl, map, boolean?, not, take, last.

What I have so far is:

(define inverse-tree
  (lambda (tree)
    (cond ((eq? '() tree) '())
        ((pair? tree) 
         (make-tree (inverse-tree (car tree))
                    (inverse-tree (cdr tree))))
        (else (tree)))))

edited Apr 24 '18 at 18:26

asked Apr 24 '18 at 18:12

Adam Morad

Start by identifying where this code is returning a value as opposed to a sub-tree; then it should be easy. – Scott Hunter Apr 24 '18 at 18:14
1

Instead of making a new question you should edit and add to your original one. – Sylwester Apr 24 '18 at 19:55

Scheme altering tree values

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