day 4 part 1 in elisp

elisp/day-4/solution.el

@@ -0,0 +1,79 @@
+#!/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 "../")
+
+(require 'ert)
+(require 'cl-lib)
+(require 'advent-of-code)
+
+(defvar solution-input
+  "../../input/day-4.txt")
+
+(defvar solution-example-input
+  "../../input/day-4-example.txt")
+
+(defun solution-parse-pair (s)
+  (let ((parts (string-split s "-")))
+    (cons (string-to-number (car parts))
+          (string-to-number (cadr parts)))))
+
+(defun solution-parse-pairs (line)
+  (let ((unparsed-pairs (string-split line "," t)))
+    (list (solution-parse-pair (car unparsed-pairs))
+          (solution-parse-pair (cadr unparsed-pairs)))))
+
+(defun solution-pair-contains? (a b)
+  (and (<= (car a) (car b))
+       (>= (cdr a) (cdr b))))
+
+(defun solution-pair-overlaps? (a b)
+  (or (and (>= (car a) (car b))
+           (<= (car a) (cdr b)))
+      (and (>= (cdr a) (car b))
+           (<= (cdr a) (cdr b)))))
+
+(defun solution-part-1 (input)
+  (let ((pairs (seq-map 'solution-parse-pairs input)))
+    (seq-count (lambda (pair)
+                   (or (solution-pair-contains? (car pair) (cadr pair))
+                       (solution-pair-contains? (cadr pair) (car pair))))
+               pairs)))
+
+(defun solution-part-2 (input)
+  (let ((pairs (seq-map 'solution-parse-pairs input)))
+    (seq-count (lambda (pair)
+                 (or (solution-pair-overlaps? (car pair) (cadr pair))
+                     (solution-pair-overlaps? (cadr pair) (car pair))))
+               pairs)))
+
+(ert-deftest solution-part-1-example ()
+  (should (equal (solution-part-1 (aoc-read-file-lines solution-example-input)) 2)))
+
+(ert-deftest solution-part-1 ()
+  (should (equal (solution-part-1 (aoc-read-file-lines solution-input)) 644)))
+
+(when noninteractive
+  (ert-run-tests-batch))
+
+;; Code
+
+;; Local Variables:
+;; read-symbol-shorthands: (("solution-" . "advent-of-code-day-4-") ("aoc-" . "advent-of-code-"))
+;; End:

input/day-4-example.txt

@@ -0,0 +1,6 @@
+2-4,6-8
+2-3,4-5
+5-7,7-9
+2-8,3-7
+6-6,4-6
+2-6,4-8