diff options
| -rw-r--r-- | day15 | 27 | ||||
| -rw-r--r-- | day15.rkt | 50 |
2 files changed, 77 insertions, 0 deletions
diff --git a/day15 b/day15 new file mode 100644 index 0000000..ea493e7 --- /dev/null +++ b/day15 @@ -0,0 +1,27 @@ +Sensor at x=1326566, y=3575946: closest beacon is at x=1374835, y=2000000 +Sensor at x=2681168, y=3951549: closest beacon is at x=3184941, y=3924923 +Sensor at x=3959984, y=1095746: closest beacon is at x=3621412, y=2239432 +Sensor at x=3150886, y=2479946: closest beacon is at x=3621412, y=2239432 +Sensor at x=3983027, y=2972336: closest beacon is at x=4012908, y=3083616 +Sensor at x=3371601, y=3853300: closest beacon is at x=3184941, y=3924923 +Sensor at x=3174612, y=3992719: closest beacon is at x=3184941, y=3924923 +Sensor at x=3316368, y=1503688: closest beacon is at x=3621412, y=2239432 +Sensor at x=3818181, y=2331216: closest beacon is at x=3621412, y=2239432 +Sensor at x=3960526, y=3229321: closest beacon is at x=4012908, y=3083616 +Sensor at x=61030, y=3045273: closest beacon is at x=-467419, y=2369316 +Sensor at x=3635583, y=3121524: closest beacon is at x=4012908, y=3083616 +Sensor at x=2813357, y=5535: closest beacon is at x=3595763, y=-77322 +Sensor at x=382745, y=1566522: closest beacon is at x=1374835, y=2000000 +Sensor at x=3585664, y=538632: closest beacon is at x=3595763, y=-77322 +Sensor at x=3979654, y=2158646: closest beacon is at x=3621412, y=2239432 +Sensor at x=3996588, y=2833167: closest beacon is at x=4012908, y=3083616 +Sensor at x=3249383, y=141800: closest beacon is at x=3595763, y=-77322 +Sensor at x=3847114, y=225529: closest beacon is at x=3595763, y=-77322 +Sensor at x=3668737, y=3720078: closest beacon is at x=3184941, y=3924923 +Sensor at x=1761961, y=680560: closest beacon is at x=1374835, y=2000000 +Sensor at x=2556636, y=2213691: closest beacon is at x=3621412, y=2239432 +Sensor at x=65365, y=215977: closest beacon is at x=346716, y=-573228 +Sensor at x=709928, y=2270200: closest beacon is at x=1374835, y=2000000 +Sensor at x=3673956, y=2670437: closest beacon is at x=4029651, y=2547743 +Sensor at x=3250958, y=3999227: closest beacon is at x=3184941, y=3924923 +Sensor at x=3009537, y=3292368: closest beacon is at x=3184941, y=3924923 diff --git a/day15.rkt b/day15.rkt new file mode 100644 index 0000000..c31b64a --- /dev/null +++ b/day15.rkt @@ -0,0 +1,50 @@ +#lang racket +;; ala https://github.com/narimiran/AdventOfCode2022/blob/main/clojure/day15.clj + +(define data + (for/list ([line (file->lines "day15")]) + (map string->number (regexp-match* #rx"[0-9]+" line)))) + +(define (dist x1 y1 x2 y2) + (+ (abs (- x1 x2)) + (abs (- y1 y2)))) + +(define (seen-in-row row) + (append-map (lambda (line) + (let* ([sx (first line)] + [sy (second line)] + [r (dist sx sy (third line) (fourth line))] + [d (- r (abs (- row sy)))]) + (if (positive? d) + (list (list (- sx d) (+ sx d))) + (list)))) + data)) + +(define (part1) + (let* ([seen (seen-in-row 2000000)] + [a (first (first (sort seen < #:key first)))] + [b (second (first (sort seen > #:key second)))]) + (- b a))) + +(part1) +;; 5147333 + +(define (find-a-hole seen) + (let loop ([highest 0] + [seen (sort seen < #:key first)]) + (if (null? seen) + #f + (if (<= (caar seen) (+ highest 1)) + (loop (max highest (cadar seen)) (rest seen)) + (- (caar seen) 1))))) + +(define (part2) + (let loop ([row 4000000]) + (let* ([seen (seen-in-row row)] + [hole (find-a-hole seen)]) + (if hole + (+ (* 4000000 hole) row) + (loop (- row 1)))))) + +(part2) +;; 13734006908372 |