advent-2025/p10/p10.org

Solution to p10

  (with-temp-buffer
    (insert-file-contents "input-test")
    (advent/replace-multiple-regex-buffer
     '(("," . " ")
       ("^" . "(")
       ("$" . ")")
       ("\\[" . "\"")
       ("\\]" . "\"")
       ("{" . "(")
       ("}" . ")")
       ))
    (goto-char (point-min))
    (insert "(setq data '(")
    (goto-char (point-max))
    (insert "))")
    (eval-buffer))

  (defun zero-one (n)
    (if (eq n ?#) 1 0))

  (setq cleanedup-data (--map (cons (-map #'zero-one (advent/split-string-into-char-list (car it))) (cdr it)) data))

for part 1 we do not need the last item

  (setq machines (--map (-drop-last 1 it) cleanedup-data))

  (defun to-bin (l)
    (-sum  (--map-indexed (* it (expt 2 it-index)) l)))

  (defun to-mask (l)
    (-sum (--map (expt 2 it) l)))

  (setq mask-machines (--map (cons (to-bin (car it)) (-map #'to-mask (cdr it))) machines))

  (-sum
   (-map (lambda (machine) 
  	 (-min (-map 'length  (--filter (= (car machine) (apply 'logxor it))
  					(-powerset (cdr machine))))))
         mask-machines))

7