commit 77fbe5b8ee110dab013ddd64fbb081e9a3313138
parent b459c50dee0cc573c8cf4e11a1c1b7c67b93ed54
Author: Natasha Kerensikova <natgh@instinctive.eu>
Date: Wed, 13 Dec 2023 17:52:44 +0000
Add day 13 reference and solution
Diffstat:
| A | day13.scm | | | 172 | +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
| A | ref/day13.txt | | | 15 | +++++++++++++++ |
2 files changed, 187 insertions(+), 0 deletions(-)
diff --git a/day13.scm b/day13.scm
@@ -0,0 +1,172 @@
+; Copyright (c) 2023, Natacha Porté
+;
+; Permission to use, copy, modify, and distribute this software for any
+; purpose with or without fee is hereby granted, provided that the above
+; copyright notice and this permission notice appear in all copies.
+;
+; THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+; WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+; MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+; ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+; WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+; ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+; OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+(import (chicken io) (chicken string)
+ comparse
+ srfi-1
+ srfi-14)
+
+;;;;;;;;;;;;;;;;;
+;; Input parsing
+
+(define symbol
+ (in #\. #\#))
+
+(define line
+ (sequence* ((data (one-or-more symbol))
+ (_ (is #\newline)))
+ (result data)))
+
+(define area
+ (sequence* ((lines (one-or-more line))
+ (_ (zero-or-more (is #\newline))))
+ (result lines)))
+
+(define all-data
+ (zero-or-more area))
+
+(define data (parse all-data (read-string)))
+
+(define (draw-area prefix m)
+ (unless (null? m)
+ (write-line (conc prefix (list->string (car m))))
+ (draw-area prefix (cdr m))))
+
+;(let ((count 0))
+; (for-each (lambda (area) (set! count (add1 count)) (draw-area (conc count ": ") area)) data))
+
+;(write-line "Input:")
+;(draw-area " " data)
+
+;;;;;;;;;;;;;;;;;
+;; First Puzzle
+
+(define (is-reflect-or-null? first second)
+ (or (null? first)
+ (null? second)
+ (and (equal? (car first) (car second))
+ (is-reflect-or-null? (cdr first) (cdr second)))))
+
+(define (is-reflect? first second)
+ (and (not (null? first))
+ (not (null? second))
+ (is-reflect-or-null? first second)))
+
+(define (reflect-indices l)
+;(let ((result
+ (let loop ((reflected (list (car l)))
+ (todo (cdr l))
+ (acc '()))
+ (if (null? todo)
+ (reverse acc)
+ (loop (cons (car todo) reflected)
+ (cdr todo)
+ (if (is-reflect-or-null? reflected todo)
+ (cons (length reflected) acc)
+ acc)))))
+;)(write-line (conc "reflect-indices " l " -> " result)) result))
+
+(define (merge-cols left right)
+;(let ((result
+ (let loop ((todo-1 left)
+ (todo-2 right)
+ (acc '()))
+ (cond ((or (null? todo-1) (null? todo-2)) (reverse acc))
+ ((< (car todo-1) (car todo-2)) (loop (cdr todo-1) todo-2 acc))
+ ((> (car todo-1) (car todo-2)) (loop todo-1 (cdr todo-2) acc))
+ (else (loop (cdr todo-1) (cdr todo-2) (cons (car todo-1) acc))))))
+;)(write-line (conc "result " left " " right " -> " result)) result))
+
+(define (reflect-cols area)
+ (let loop ((todo (cdr area))
+ (acc (reflect-indices (car area))))
+ (if (null? todo)
+ (begin (assert (<= (length acc) 1)) acc)
+ (loop (cdr todo)
+ (merge-cols acc (reflect-indices (car todo)))))))
+
+(define (term-1 area)
+ (let ((cols (reflect-cols area))
+ (rows (reflect-indices area)))
+; (write-line (conc "cols: " cols ", rows: " rows))
+ (unless (= (+ (length cols) (length rows)) 1)
+ (write-line (conc "== cols: " cols ", rows: " rows))
+ (draw-area " " area))
+ (assert (= 1 (+ (length cols) (length rows))))
+ (+ (apply + cols) (* 100 (apply + rows)))))
+
+;(let ((count 0))
+; (for-each
+; (lambda (area) (set! count (add1 count))
+; (write-line (conc count ": " (term-1 area))))
+; data))
+
+(write-line (conc "First puzzle: "
+ (apply + (map (lambda (area) (term-1 area)) data))))
+
+;;;;;;;;;;;;;;;;;
+;; Second Puzzle
+
+(define (reflect-cols* area)
+ (let loop ((todo (cdr area))
+ (acc (reflect-indices (car area))))
+ (if (null? todo)
+ acc
+ (loop (cdr todo)
+ (merge-cols acc (reflect-indices (car todo)))))))
+
+(define (term-1* area prev-term)
+; (write-line (conc "term-1* " area))
+;(let ((result
+ (let ((cols (filter (lambda (i) (not (= i prev-term))) (reflect-cols* area)))
+ (rows (filter (lambda (i) (not (= prev-term (* 100 i)))) (reflect-indices area))))
+;(write-line (conc " cols: " cols ", rows: " rows))
+ (if (= (+ (length cols) (length rows)) 1)
+ (+ (apply + cols) (* 100 (apply + rows)))
+ 0)))
+;)(write-line (conc " -> " result)) result))
+
+(define (term-2 area)
+ (let ((prev-term (term-1 area)))
+ (let loop ((prev-lines '())
+ (prev-cols '())
+ (next-cols (car area))
+ (next-lines (cdr area)))
+ (if (null? next-cols)
+ (loop (append prev-lines (list (reverse prev-cols)))
+ '()
+ (car next-lines)
+ (cdr next-lines))
+ (let ((try (term-1* (append prev-lines
+ (list (append (reverse prev-cols)
+ (if (eqv? (car next-cols) #\#)
+ '(#\.) '(#\#))
+ (cdr next-cols)))
+ next-lines)
+ prev-term)))
+ (if (> try 0)
+ try
+ (loop prev-lines
+ (cons (car next-cols) prev-cols)
+ (cdr next-cols)
+ next-lines)))))))
+
+;(let ((count 0))
+; (for-each
+; (lambda (area) (set! count (add1 count))
+; (write-line (conc count ": " (term-2 area))))
+; data))
+
+(write-line (conc "Second puzzle: "
+ (apply + (map (lambda (area) (term-2 area)) data))))
diff --git a/ref/day13.txt b/ref/day13.txt
@@ -0,0 +1,15 @@
+#.##..##.
+..#.##.#.
+##......#
+##......#
+..#.##.#.
+..##..##.
+#.#.##.#.
+
+#...##..#
+#....#..#
+..##..###
+#####.##.
+#####.##.
+..##..###
+#....#..#
