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author | H.J <thechairman@thechairman.info> | 2024-10-09 11:36:55 -0400 |
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committer | H.J <thechairman@thechairman.info> | 2024-10-09 11:36:55 -0400 |
commit | 8777ff071f7bb37631baa7b6717ad29961e50911 (patch) | |
tree | 6d59c4ed58e454b960339c3d1151f0a879e8d7cb /aoc2021/day-12/day-12.rkt | |
parent | 6156a9ef7be4012063a042aafb4e9b0d7eadde8e (diff) | |
download | gleam_aoc-8777ff071f7bb37631baa7b6717ad29961e50911.tar.gz gleam_aoc-8777ff071f7bb37631baa7b6717ad29961e50911.zip |
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Diffstat (limited to 'aoc2021/day-12/day-12.rkt')
-rw-r--r-- | aoc2021/day-12/day-12.rkt | 38 |
1 files changed, 0 insertions, 38 deletions
diff --git a/aoc2021/day-12/day-12.rkt b/aoc2021/day-12/day-12.rkt deleted file mode 100644 index 18ed86f..0000000 --- a/aoc2021/day-12/day-12.rkt +++ /dev/null @@ -1,38 +0,0 @@ -#lang racket -(require "../../jj-aoc.rkt" - threading) - -(define path-pairs - (for/list ([l (in-lines (open-day 12 2021))]) - (match (string-split l "-") - [(list start end) (cons start end)]))) - -(define edges-hash (make-hash)) - -(for ([pair (in-list path-pairs)]) - (match-define (cons start end) pair) - (hash-update! edges-hash start (curry cons end) '()) - (hash-update! edges-hash end (curry cons start) '())) - -;; part 1 -(define (backtracking-disallowed? next prevs) - (and (equal? (string-downcase next) next) (member next prevs))) - -(define (look-for-next-cave [path-list '("start")] #:only-one-visit? [visit-used-up? #t]) - (define current-cave (car path-list)) - (cond - [(equal? current-cave "end") (list path-list)] - [else - (~>> (for/list ([next-path (in-list (hash-ref edges-hash current-cave null))] - #:when (and (not (equal? next-path "start")) - (not (and (backtracking-disallowed? next-path path-list) - visit-used-up?)))) - (look-for-next-cave - (cons next-path path-list) - #:only-one-visit? (or (backtracking-disallowed? next-path path-list) visit-used-up?))) - (apply append))])) - -(~> (look-for-next-cave) length time) - -;; part 2 -(~> (look-for-next-cave #:only-one-visit? #f) length time) |