diff options
Diffstat (limited to '2020/day-16/day-16.rkt')
-rw-r--r-- | 2020/day-16/day-16.rkt | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/2020/day-16/day-16.rkt b/2020/day-16/day-16.rkt new file mode 100644 index 0000000..64271c7 --- /dev/null +++ b/2020/day-16/day-16.rkt @@ -0,0 +1,34 @@ +#lang racket + +(require advent-of-code + relation + threading + rebellion/base/range) + +(struct field-rule (name range1 range2) #:transparent) + +(define (make-lines strs) + (string-split strs "\n")) +(define (seperate-fields strs) + (~>> (string-split strs ",") (map ->number))) + +(define (process-rules str) + (match str + [(regexp + #px"(.+): (\\d+)-(\\d+) or (\\d+)-(\\d+)" + (list _ name (app ->number min1) (app ->number max1) (app ->number min2) (app ->number max2))) + (field-rule name (closed-range min1 max1) (closed-range min2 max2))])) + +(match-define (list (app (λ~>> make-lines (map process-rules)) ticket-rules) + (app (λ~>> make-lines second seperate-fields) your-ticket) + (app (λ~>> make-lines rest (map seperate-fields)) other-tickets)) + (~> (fetch-aoc-input (find-session) 2020 16) (string-split "\n\n"))) + +(define (ticket-scanning-error-rate ticket rules) + (for/sum ([ticket-field (in-list ticket)] + [ticket-rule (in-list rules)] + #:do [(match-define (field-rule _ r1 r2) ticket-rule)] + #:unless (or (range-contains? r1 ticket-field) (range-contains? r2 ticket-field))) + ticket-field)) + +(for/sum ([ticket (in-list other-tickets)]) (ticket-scanning-error-rate ticket ticket-rules))
\ No newline at end of file |