67 lines
1.9 KiB
Racket
67 lines
1.9 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 8
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(struct insn [type arg] #:transparent)
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;; helper functions here
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(define (part1 input)
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(define (execute pc acc [seen (mutable-set)])
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(if (set-member? seen pc)
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acc
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(let ([in (list-ref input pc)])
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(set-add! seen pc)
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(match (insn-type in)
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["nop" (execute (add1 pc) acc seen)]
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["jmp" (execute (+ pc (insn-arg in)) acc seen)]
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["acc" (execute (add1 pc) (+ acc (insn-arg in)) seen)]
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[x (error "not shonks" x)]))))
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(execute 0 0))
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(define (part2 input)
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(define (execute-actual input)
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(define (execute pc acc [seen (mutable-set)])
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(if (>= pc (length input))
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acc
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(let ([in (list-ref input pc)])
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(set-add! seen pc)
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(match (insn-type in)
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["nop" (execute (add1 pc) acc seen)]
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["jmp" (execute (+ pc (insn-arg in)) acc seen)]
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["acc" (execute (add1 pc) (+ acc (insn-arg in)) seen)]
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[x (error "not shonks" x)]))))
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(execute 0 0))
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(define target-pc (length input))
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(for ([in (in-list input)] [i (in-naturals)] #:unless (string=? "acc" (insn-type in)))
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(define new-type (if (string=? (insn-type in) "jmp") "nop" "jmp"))
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(define new-insn (insn new-type (insn-arg in)))
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;; aaaa
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(define vec (vector-copy (list->vector input)))
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(vector-set! vec i new-insn)
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(define new-prg (vector->list vec))
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(with-handlers ([exn? (lambda (x) (answer 8 2 (execute-actual new-prg)))])
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(part1 new-prg))))
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(module+ test
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(require rackunit)
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;; tests here
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(displayln "no tests :("))
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(module+ main
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(define input
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(for/list ([line (in-list (file->lines "inputs/8"))])
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(match (string-split line)
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[(list a b) (insn a (string->number b))]
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[x (error "not shonks" x)])))
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;; part 1
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(answer 8 1 (part1 input))
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;; part 2
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(answer 8 2 (part2 input))
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(displayln "meow"))
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