52 lines
1.6 KiB
Racket
52 lines
1.6 KiB
Racket
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#lang curly-fn racket
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(require "scripts/aoc.rkt")
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;; solution for day 7
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(define (part1 adjlist all-colors wanted)
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(define (dfs src dest)
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(for/or ([item (in-list (hash-ref adjlist src '()))])
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(or (dfs (car item) dest) (string=? (car item) dest))))
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;; bad solution
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(for/sum ([src (in-set all-colors)])
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(if (dfs src wanted) 1 0)))
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(define (part2 adjlist all-colors wanted)
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(define (part2-impl src)
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(add1
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(for/sum ([subbag (in-list (hash-ref adjlist src '()))])
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(* (cdr subbag) (part2-impl (car subbag))))))
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(sub1 (part2-impl wanted)))
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(module+ main
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(define input (file->lines "inputs/7"))
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(define all-colors (mutable-set))
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(define adjlist
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(for/hash ([line (in-list input)])
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(match line
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[(pregexp #px"^([a-z ]+) bags contain ([^\\.]+).$" (list _ src-color contains))
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(set-add! all-colors src-color)
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(values src-color
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(if (string=? "no other bags" contains)
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'()
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(for/list ([item (in-list (string-split contains ", "))])
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(match item
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[(pregexp #px"^([0-9]+) ([a-z ]+) bag[s]?"
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(list _ (app string->number number) color))
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(set-add! all-colors color)
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(cons color number)]
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[x (error "not shonks" x)]))))]
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[x (error "not shonks" x)])))
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(define wanted "shiny gold")
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;; part 1
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(answer 7 1 (part1 adjlist all-colors wanted))
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;; part 2
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(answer 7 2 (part2 adjlist all-colors wanted))
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(displayln "meow"))
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