(require :uiop)
(load (sb-ext:posix-getenv "ASDF"))
(asdf:load-system 'cl-heap)

(defun bank-max-joltage-step (known-buffer unknown-buffer depth)
  ;; (format t "~A:~A~%" known-buffer unknown-buffer)
  (if (= (length known-buffer) depth)
    (parse-integer known-buffer)
    (loop for i from 0 to (- (length unknown-buffer) (- depth (length known-buffer)))
      collect
      (let* (
            (digit (subseq unknown-buffer i (+ i 1)))
            (new-unknown-buffer (subseq unknown-buffer (+ i 1)))
            (new-known-buffer (format nil "~A~A" known-buffer digit)))
        (list (- 0 (parse-integer new-known-buffer)) new-known-buffer new-unknown-buffer depth)))))
(bank-max-joltage-step "" "234234234234278" 2)

(defun bank-max-joltage (bank depth)
  (defparameter *queue* (make-instance 'cl-heap:priority-queue))
  (cl-heap:enqueue *queue* (list "" bank depth) 0)
  (loop
    do (defparameter *candidate* (apply #'bank-max-joltage-step (cl-heap:dequeue *queue*)))
    when (integerp *candidate*) do (return *candidate*)
    do (loop for branch in (reverse *candidate*)
             do (cl-heap:enqueue *queue* (cdr branch) (car branch)))))
(bank-max-joltage "234234234234278" 2)
(bank-max-joltage "234234234234278" 12)

(defun bank-max-joltage12 (bank)
  (bank-max-joltage bank 12))
(defun array-total-joltage (bank-list depth)
  (reduce #'+
    (mapcar #'bank-max-joltage12 bank-list)))

(array-total-joltage (uiop:read-file-lines "03example.txt") 12)
(array-total-joltage (uiop:read-file-lines "03data.txt") 12)