素因数分解

soinsuu.lsp

(defun bunkai (n)
  (let ((limit (floor (sqrt n))))
    (labels ((f (n divisor acc)
                (if (and (not (= 1 n))
                         (<= divisor limit))
                  (if (zerop (mod n divisor))
                    (f (/ n divisor)
                       divisor
                       (cons divisor acc))
                    (f n
                       (1+ divisor)
                       acc))
                  (remove 1 (cons n acc)))))
      (f n 2 ()))))

(compile 'bunkai)
(prin1 (bunkai (read)))