6.lisp

(let ((points (mapcar #'parse-integer (str:split "," (car (uiop:read-file-lines "~/builds/web/input"))))))
  (let ((state (make-array 10 :initial-element 0)))
    (loop for point in points do
      (incf (aref state point)))
    (loop for day below 256 do
      (progn
        (let ((new (aref state 0)))
          (loop for i from 0 below 8 do
            (setf (aref state i)
                  (aref state (1+ i))))
          (incf (aref state 6) new)
          (setf (aref state 8) new))))
    (loop for x across state summing x)))