August 19, 2024
P08 - Eliminate consecutive duplicates of list elements
If a list contains repeated elements they should be replaced with a single copy of the element. The order of the elements should not be changed.
Example:* (compress '(a a a a b c c a a d e e e e))(A B C A D E)
lisp
(defun compress (list)
(cond
((null list) nil)
((null (cdr list)) list)
;; if the first item (list) and' equal to the consecutive
;; (first of the rest)
((eql (first list) (first (rest list)))
;; find it ignores the first of the list and continues recursively in the rest
(compress (rest list)))
(t (cons (first list) (compress (rest list))))
)
)
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