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#lang racket
(require threading
list-utils
"../../jj-aoc.rkt")
(struct trial-data (signal output) #:transparent)
(define (string->sets s)
(~> s string-split (map (λ~> string->list list->set) _)))
(define data
(for/list ([l (in-lines (open-day 8))] #:unless (equal? l ""))
(~> l (string-split _ " | ") (map string->sets _) (apply trial-data _))))
;; part 1
(for*/sum ([trial (in-list data)] [output (in-list (trial-data-output trial))]
#:when (ormap (λ~> (= (set-count output))) '(2 3 4 7)))
1)
;; part 2
(define (matching-pattern len trial)
(define solution-set
(for*/list ([signal (in-list (trial-data-signal trial))] #:when (= (set-count signal) len))
signal))
(match solution-set
[(list s) s]
[s (apply set-intersect s)]))
(define (determine-arrangement t)
(let* ([pattern-1 (matching-pattern 2 t)]
[pattern-4 (matching-pattern 4 t)]
[pattern-7 (matching-pattern 3 t)]
[pattern-8 (matching-pattern 7 t)]
[pattern-shared-235 (matching-pattern 5 t)]
[pattern-3 (set-union pattern-1 pattern-shared-235)]
[pattern-9 (set-union pattern-4 pattern-shared-235)]
[pattern-shared-069 (matching-pattern 6 t)]
[pattern-just-f (set-subtract pattern-shared-069 pattern-shared-235)]
[pattern-just-e
(set-subtract pattern-8 (set-union pattern-4 pattern-shared-235 pattern-shared-069))]
[pattern-2 (set-union (set-subtract pattern-3 pattern-just-f) pattern-just-e)]
[pattern-just-c (set-subtract (set-intersect pattern-4 pattern-7) pattern-just-f)]
[pattern-6 (set-subtract pattern-8 pattern-just-c)]
[pattern-5 (set-subtract pattern-6 pattern-just-e)]
[pattern-0 (set-union (set-subtract pattern-8 pattern-shared-235) pattern-shared-069)])
(~> (list pattern-0
pattern-1
pattern-2
pattern-3
pattern-4
pattern-5
pattern-6
pattern-7
pattern-8
pattern-9)
enumerate
make-hash)))
(for/sum ([trial (in-list data)])
(~>> trial
trial-data-output
(map (λ~>> (hash-ref (determine-arrangement trial))))
(apply ~a)
string->number))
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