aoc-2022/elisp/day-5/solution.el
2022-12-10 02:40:28 -05:00

121 lines
4.2 KiB
EmacsLisp
Executable file

#!/usr/bin/env -S emacs --script
;; -*- lexical-binding: t; -*-
;; Copyright (C) 2022 notroot
;; This program is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.
;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;; You should have received a copy of the GNU General Public License
;; along with this program. If not, see <https://www.gnu.org/licenses/>.
(add-to-list 'load-path default-directory)
(require 'cl-lib)
(require 'eieio)
(require 'ert)
(require 'advent-of-code)
(defmacro -make-crates (&rest exprs)
`(make-advent-of-code-day-5-crates ,@exprs))
(cl-defstruct -crates
stacks)
(defun -crates-pop (crates n)
(with-slots (stacks) crates
(when-let ((stack (assoc n stacks)))
(pop (cdr stack)))))
(defun -crates-push (crates crate n)
(with-slots (stacks) crates
(if-let ((stack (assoc n stacks)))
(push crate (cdr stack))
(push (cons n (list crate)) stacks))))
(defun -crates-append (crates crate n)
(with-slots (stacks) crates
(if-let ((stack (assoc n stacks)))
(setf (cdr stack) (append (cdr stack) (list crate)))
(push (cons n (list crate)) stacks))))
(defun -crates-process-move (crates move)
(with-slots (n from to) move
(cl-loop repeat n
do (-crates-push crates (-crates-pop crates (- from 1)) (- to 1)))))
(defun -crates-from-list (input)
(cl-loop for (crate . n) in input
with crates = (-make-crates :stacks nil)
do (-crates-append crates crate n)
finally (return crates)))
(defmacro -make-move (&rest exprs)
`(make-advent-of-code-day-5-move ,@exprs))
(cl-defstruct -move
n from to)
(defun -parse-input-into-parts (input)
(let* ((delimiter (seq-position input "" 'string=))
(crates (seq-subseq input 0 (- delimiter 1)))
(moves (seq-subseq input (+ delimiter 1))))
(list crates moves)))
(defun -parse-crates-from-line (line)
(cl-loop for i from 0 to (- (length line) 3) by 4
for n from 0
for crate = (substring line i (+ i 3))
for crate-id = (substring crate 1 2)
for empty? = (not (string-match-p "[^\s\n]" crate))
if (not empty?)
collect (cons crate-id n)))
(defun -parse-move-from-line (line)
(save-match-data
(string-match (rx "move" space (group (one-or-more digit)) space
"from" space (group (one-or-more digit)) space
"to" space (group (one-or-more digit)))
line)
(list (string-to-number (match-string 1 line))
(string-to-number (match-string 2 line))
(string-to-number (match-string 3 line)))))
(defun -part-1 (input)
(pcase-let* ((`(,input-crates ,input-moves) (-parse-input-into-parts input))
(parsed-crates-list (cl-loop for line in input-crates
append (-parse-crates-from-line line)))
(crates (-crates-from-list parsed-crates-list))
(moves (cl-loop for line in input-moves
for move = (pcase-let ((`(,n ,from ,to) (-parse-move-from-line line)))
(-make-move :n n :from from :to to))
collect move)))
(seq-do (lambda (move)
(-crates-process-move crates move))
moves)
(cl-loop for n from 0 to (length (-crates-stacks crates))
for top-crate = (cadr (assoc n (-crates-stacks crates)))
for top-crates = top-crate then (concat top-crates top-crate)
finally (return top-crates))))
(ert-deftest -test-part-1-example ()
(should (equal (-part-1 (aoc-read-file-lines "example.txt")) "CMZ")))
(ert-deftest -test-part-1 ()
(should (equal (-part-1 (aoc-read-file-lines "input.txt")) "CFFHVVHNC")))
(when noninteractive
(ert-run-tests-batch))
;; Local Variables:
;; read-symbol-shorthands: (("-" . "advent-of-code-day-5-") ("aoc-" . "advent-of-code-"))
;; End: