diff options
Diffstat (limited to 'aoc2023-racket/day-24/day-24a.rkt')
-rw-r--r-- | aoc2023-racket/day-24/day-24a.rkt | 51 |
1 files changed, 0 insertions, 51 deletions
diff --git a/aoc2023-racket/day-24/day-24a.rkt b/aoc2023-racket/day-24/day-24a.rkt deleted file mode 100644 index 31f526d..0000000 --- a/aoc2023-racket/day-24/day-24a.rkt +++ /dev/null @@ -1,51 +0,0 @@ -#lang rosette - -(require advent-of-code - threading) - -(struct hail (posn vel) #:transparent) -(struct posn (x y z) #:transparent) -(struct vel (x y z) #:transparent) - -(define input (fetch-aoc-input (find-session) 2023 24 #:cache #true)) - -(define LOWER-BOUND 200000000000000) -(define UPPER-BOUND 400000000000000) - -(define (->struct f str) - (~> str (string-split _ ",") (map (λ~> string-trim string->number) _) (apply f _))) - -(define (parse-hail-record str) - (match-define (list p v) (string-split str " @ ")) - (hail (->struct posn p) - (->struct vel v))) - -(define hail-paths - (for/list ([hail (in-list (string-split input "\n"))]) - (parse-hail-record hail))) - -;; part 1 -(define (valid-intersection? h1 h2) - (match-define (hail (posn x1 y1 _) (vel vx1 vy1 _)) h1) - (match-define (hail (posn x2 y2 _) (vel vx2 vy2 _)) h2) - (cond - [(= (* vy1 vx2) (* vx1 vy2)) #f] - [else - (define t1 (/ (- (* vy2 (- x1 x2)) (* vx2 (- y1 y2))) - (- (* vy1 vx2) (* vx1 vy2)))) - (define t2 (/ (- (* vy1 (- x2 x1)) (* vx1 (- y2 y1))) - (- (* vy2 vx1) (* vx2 vy1)))) - - (define x (+ x1 (* t1 vx1))) - (define y (+ y1 (* t1 vy1))) - - (and (<= LOWER-BOUND x UPPER-BOUND) - (<= LOWER-BOUND y UPPER-BOUND) - (<= 0 t1) - (<= 0 t2))])) - -(for/sum ([(trial-paths) (in-combinations hail-paths 2)] ; - #:when (apply valid-intersection? trial-paths)) - 1) - -;; part 2 - see day-24b.rkt |