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-rw-r--r--aoc2023-racket/day-03/day-03.rkt72
1 files changed, 0 insertions, 72 deletions
diff --git a/aoc2023-racket/day-03/day-03.rkt b/aoc2023-racket/day-03/day-03.rkt
deleted file mode 100644
index 60e81a6..0000000
--- a/aoc2023-racket/day-03/day-03.rkt
+++ /dev/null
@@ -1,72 +0,0 @@
-#lang racket
-
-(require advent-of-code
- threading)
-
-(struct posn (x y) #:transparent)
-(struct part (n posns) #:transparent)
-
-(define (make-board port)
- (for*/hash ([(row y) (in-indexed (port->lines port))]
- [(col x) (in-indexed (string->list row))]
- #:unless (equal? col #\.))
- (define v
- (cond
- [(string->number (string col))]
- [(equal? col #\*) 'gear]
- [else 'other]))
- (values (posn x y) v)))
-
-(define board (~> (open-aoc-input (find-session) 2023 3 #:cache #true) make-board))
-
-(define (posn<? a b)
- (match-define (list (cons (posn a-x a-y) _) (cons (posn b-x b-y) _)) (list a b))
- (if (= a-y b-y) (< a-x b-x) (< a-y b-y)))
-
-(define (find-cells f b)
- (~> (for/hash ([(k v) (in-hash b)] #:when (f v))
- (values k v))
- hash->list
- (sort posn<?)))
-
-(define (group-into-parts cells [acc '()])
- (match* (cells acc)
- [('() acc)
- acc]
- [((list* (cons (and pt (posn x y)) n) cs)
- (list* (part n* (and pts (list* (posn x* y) rest-pts)))
- rest-acc))
- #:when (= (- x x*) 1)
- (group-into-parts cs (cons (part (+ n (* n* 10)) (cons pt pts)) rest-acc))]
- [((list* (cons pt n) cs) acc)
- (group-into-parts cs (cons (part n (list pt)) acc))]))
-
-(define (neighbors p)
- (for*/list ([dx '(-1 0 1)]
- [dy '(-1 0 1)]
- #:unless (and (= dx 0) (= dy 0)))
- (posn (+ dx (posn-x p)) (+ dy (posn-y p)))))
-
-(define to-neighbors (λ~>> part-posns (append-map neighbors) remove-duplicates))
-(define (symbol-in-neighbors b pt acc)
- (~>> pt
- to-neighbors
- (ormap (λ (p) (let ([lookup (hash-ref b p #f)])
- (or (equal? lookup 'gear) (equal? lookup 'other)))))
- ((λ (bool) (if bool (+ acc (part-n pt)) acc)))))
-
-;; part 1
-(define parts (~>> board (find-cells integer?) group-into-parts))
-(foldl (curry symbol-in-neighbors board) 0 parts)
-
-;; part 2
-(define gears (~>> board (find-cells (curry equal? 'gear)) (map car)))
-(define parts-with-neighbors (map (λ (pt) (struct-copy part pt [posns (to-neighbors pt)])) parts))
-
-(define (find-parts-near-gear pts gear)
- (filter-map (λ (pt) (and (findf (curry equal? gear) (part-posns pt)) (part-n pt))) pts))
-
-(~>> gears
- (filter-map (λ~>> (find-parts-near-gear parts-with-neighbors)
- ((λ (ns) (if (= (length ns) 2) (* (first ns) (second ns)) #f)))))
- (apply +))