#+title: solution to p11

#+begin_src emacs-lisp :results none
  (with-temp-buffer
    (insert-file-contents "input")
    (advent/replace-multiple-regex-buffer
     '((":" . " ")
       ("^" . "(")
       ("$" . ")")))
    (goto-char (point-min))
    (insert "(setq data '(")
    (goto-char (point-max))
    (insert "))")
    (eval-buffer))
#+end_src

This is for part 1
#+begin_src emacs-lisp
  (defun paths-from (label)
    (if (eq label 'out) 1
      (-sum (-map 'paths-from (cdr (assq label data))))))
  (memoize 'paths-from)
  (paths-from 'you)
#+end_src

#+RESULTS:
: 701

And this for part 2; note that there are no paths from dac to fft
(there can be only paths in one direction, otherwise we would get
a loop.
#+begin_src emacs-lisp
    (defun paths-from-to (label exit)
      (if (eq label exit) 1
        (if (eq label 'out) 0
        (-sum (--map (paths-from-to it exit) (cdr (assq label data)))))))
    (memoize 'paths-from-to)
(* (paths-from-to 'svr 'fft)
   (paths-from-to 'fft 'dac)
   (paths-from 'dac))
#+end_src

#+RESULTS:
: 390108778818526