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#lang racket
(require advent-of-code
threading)
(struct posn (x y) #:transparent)
(match-define (list raw-map raw-instructions)
(string-split (fetch-aoc-input (find-session) 2022 22 #:cache #true) "\n\n"))
(define board-map
(for*/hash ([(row y) (in-indexed (string-split raw-map "\n"))]
[(col x) (in-indexed row)]
#:unless (equal? col #\space))
(define tile
(match col
[#\. 'open]
[#\# 'wall]))
(values (posn x y) tile)))
(define instructions
(~>> raw-instructions
(regexp-match* #px"(\\d+)|R|L")
(map (match-lambda
[(? string->number n) (string->number n)]
["R" 'clockwise]
["L" 'counterclockwise]))))
(define start-tile
(~>> board-map
hash-keys
(filter (match-lambda
[(posn _ 0) #true]
[_ #false]))
(argmin posn-x)))
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