diff options
| -rw-r--r-- | 2020/day-12/day-12.rkt | 56 | ||||
| -rw-r--r-- | 2020/day-13/day-13.rkt | 32 | ||||
| -rw-r--r-- | 2022/day-06/day-06.ipynb | 3 | ||||
| -rw-r--r-- | 2022/day-06/day-06.rkt | 3 |
4 files changed, 90 insertions, 4 deletions
diff --git a/2020/day-12/day-12.rkt b/2020/day-12/day-12.rkt new file mode 100644 index 0000000..e4bbd32 --- /dev/null +++ b/2020/day-12/day-12.rkt @@ -0,0 +1,56 @@ +#lang rackjure + +(require advent-of-code + threading + (only-in relation ->symbol ->number)) + +(struct instruction (direction distance) #:transparent) + +(define (parse-instruction str) + (match str + [(regexp #px"(\\w)(\\d+)" (list _ dir dist)) (instruction (->symbol dir) (->number dist))])) + +(define instructions + (~>> (fetch-aoc-input (find-session) 2020 12) string-split (map parse-instruction))) + +;; part 1 +(struct boat (x y nav) #:transparent) + +(define (angle->direction n) + (case n + [(0) 'E] + [(90) 'N] + [(180) 'W] + [(270) 'S])) + +(define (move-via-direct-command inst b) + (match-define (boat x y facing) b) + (match inst + [(instruction 'N n) (boat x (+ y n) facing)] + [(instruction 'S n) (boat x (- y n) facing)] + [(instruction 'E n) (boat (+ x n) y facing)] + [(instruction 'W n) (boat (- x n) y facing)] + [(instruction 'L n) (boat x y (modulo (+ facing n) 360))] + [(instruction 'R n) (boat x y (modulo (- facing n) 360))] + [(instruction 'F n) (move-via-direct-command (instruction (angle->direction facing) n) b)])) + +(define (find-boat-destination using start instructions) + (match-define (boat x y _) (foldl using start instructions)) + (+ (abs x) (abs y))) + +(find-boat-destination move-via-direct-command (boat 0 0 0) instructions) + +;; part 2 +(define (move-via-waypoint inst b) + (match-define (boat x y (cons wp-x wp-y)) b) + (match inst + [(instruction 'N n) (boat x y (cons wp-x (+ wp-y n)))] + [(instruction 'S n) (boat x y (cons wp-x (- wp-y n)))] + [(instruction 'E n) (boat x y (cons (+ wp-x n) wp-y))] + [(instruction 'W n) (boat x y (cons (- wp-x n) wp-y))] + [(instruction _ 180) (boat x y (cons (- wp-x) (- wp-y)))] + [(or (instruction 'L 90) (instruction 'R 270)) (boat x y (cons (- wp-y) wp-x))] + [(or (instruction 'R 90) (instruction 'L 270)) (boat x y (cons wp-y (- wp-x)))] + [(instruction 'F n) (boat (+ x (* n wp-x)) (+ y (* n wp-y)) (cons wp-x wp-y))])) + +(find-boat-destination move-via-waypoint (boat 0 0 '(10 . 1)) instructions) diff --git a/2020/day-13/day-13.rkt b/2020/day-13/day-13.rkt new file mode 100644 index 0000000..b53f045 --- /dev/null +++ b/2020/day-13/day-13.rkt @@ -0,0 +1,32 @@ +#lang racket + +(require advent-of-code + (only-in relation ->number) + threading) + +(define (process-ids str) + (~> str (string-split ",") (filter-map (λ (s) (string->number s 10 'number-or-false)) _))) + +(match-define (regexp #px"(\\d+)\n(.+)" (list _ (app ->number timestamp) raw-bus-ids)) + (fetch-aoc-input (find-session) 2020 13)) + +(define bus-ids (process-ids raw-bus-ids)) + +;; part 1 +(for/first ([minute (in-naturals timestamp)] + #:do [(define departing-bus + (for/first ([b bus-ids] #:when (= 0 (remainder minute b))) + b))] + #:when departing-bus) + (* departing-bus (- minute timestamp))) + +;; part 2 +(for/fold ([step 1] [current-timestamp 1] #:result current-timestamp) + ([b* (in-list (string-split (string-trim raw-bus-ids) ","))] + [offset (in-naturals)] + #:unless (equal? b* "x") + #:do [(define bus (->number b*))]) + (values + (* step bus) + (for/first ([n (in-range current-timestamp +inf.0 step)] #:when (= 0 (remainder (+ n offset) bus))) + n))) diff --git a/2022/day-06/day-06.ipynb b/2022/day-06/day-06.ipynb index 3468d68..0c89fa1 100644 --- a/2022/day-06/day-06.ipynb +++ b/2022/day-06/day-06.ipynb @@ -22,7 +22,6 @@ "source": [ "(require racket\n", " advent-of-code\n", - " (only-in relation ->list)\n", " (only-in algorithms sliding))\n" ] }, @@ -64,7 +63,7 @@ " (match type\n", " ['start-of-packet 4]\n", " ['start-of-message 14]))\n", - " (for/first ([chunk (in-list (sliding (->list data) n))]\n", + " (for/first ([chunk (in-list (sliding (string->list data) n))]\n", " [i (in-naturals n)]\n", " #:when (= n (~> chunk remove-duplicates length)))\n", " i))\n", diff --git a/2022/day-06/day-06.rkt b/2022/day-06/day-06.rkt index 89b8075..1c167a6 100644 --- a/2022/day-06/day-06.rkt +++ b/2022/day-06/day-06.rkt @@ -1,7 +1,6 @@ #lang racket (require advent-of-code - (only-in relation ->list ->set) (only-in algorithms sliding)) (define buffer (fetch-aoc-input (find-session) 2022 6)) @@ -11,7 +10,7 @@ (case type [(start-of-packet) 4] [(start-of-message) 14])) - (for/first ([chunk (in-list (sliding (->list data) n))] + (for/first ([chunk (in-list (sliding (string->list data) n))] [i (in-naturals n)] #:unless (check-duplicates chunk)) i)) |