逆fizzbuzz in Common Lisp

inverse-fizzbuzz.lisp

;;; http://www.jasq.org/2/post/2012/05/inverse-fizzbuzz.html
;;; http://d.hatena.ne.jp/matarillo/20120515/p1

(ql:quickload :cl-ppcre)

(defun scan-all (re str &optional (start 0))
  (multiple-value-bind (s e) (ppcre:scan re str :start start)
    (when s (cons (list (1+ s) e) (scan-all re str (1+ s))))))

(defun inverse-fizzbuzz (fb)
  (let ((re (format nil "~{~A~^_*?~}" (mapcar #'(lambda (s) (case s (fizz "f") (buzz "b") (t "z"))) fb)))
        (pattern (format nil "~V@{__f_bf__fb_f__z~}" (+ 2 (floor (length fb) 7)) t)))
    (car (sort (scan-all re pattern) #'> :key (lambda (p) (apply #'- p))))))


(format t "~{~&~A~}"
 (mapcar #'inverse-fizzbuzz
         `((fizz)
           (buzz)
           (fizz fizz buzz)
           (fizz buzz)
           (buzz fizz)
           (fizz buzz fizz)
           (fizz fizz)
           (buzz buzz)
           (fizzbuzz fizz buzz)
           )))

; (3 3)
; (5 5)
; (6 10)
; (9 10)
; (5 6)
; (3 6)
; (6 9)
; NIL
; (15 20)