Lecture 15 Additional Problems


  ;; A ftnode is either
  ;;   - 'unknown or
  ;;   - (make-person string number symbol ftnode ftnode)
  (define-struct person (name year eye mother father))

;; Example

(define MaryTree
  (make-person "Mary" 1980 'blue
               (make-person "Ann" 1960 'green
                            'unknown
                            (make-person "Fred" 1936 'blue
                                         'unknown
                                         'unknown))
               (make-person "Joe" 1960 'blue
                            'unknown
                            'unknown)))




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  ;; count-blue-eyed : ftnode -> number
  ;; determine how many blue-eyed people are in the family tree

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  ;; gather-green-eyed : ftnode -> list-of-string
  ;; return list of names of green-eyed people in the family tree