aoc2019/7.rkt

148 lines
5.0 KiB
Racket

#lang racket
(require racket/async-channel)
;; First some helpers
(define (op-mode opcode idx)
(match (modulo (floor (/ opcode (expt 10 (+ idx 2)))) 10)
[0 'pos]
[1 'imm]
[_ (error "invalid mode")]))
(define (op-op opcode)
(modulo opcode 100))
(define (tape-ref/mode tape pos mode)
(match mode
['pos (list-ref tape (list-ref tape pos))]
['imm (list-ref tape pos)]
[_ (error "invalid mode")]))
;; Generic abstracted opcode interpreter function
;; Calls handler for opcode-specific handling, which should call callback to continue or return to
;; exit.
(define (intcode-handle-opcode callback spec handler tape pos)
(let* ([opcode (list-ref tape pos)]
[args (for/list ([spec-item spec] [idx (in-range (length spec))])
(tape-ref/mode tape (+ pos idx 1)
(match spec-item
['in (op-mode opcode idx)]
['out 'imm])))])
(apply handler callback tape (+ pos (length spec) 1) args)))
;; Create a system to register intcode ops
(struct intcode-op [code spec handler])
(define opcode-table (make-hash))
;; Evil mutation incoming!!!!
(define (intcode-register code spec handler)
(hash-set! opcode-table code (intcode-op code spec handler)))
;; Main eval function
(define (intcode-eval tape [pos 0])
(let* ([opcode (list-ref tape pos)]
[handler-entry (hash-ref opcode-table (op-op opcode))])
(intcode-handle-opcode intcode-eval
(intcode-op-spec handler-entry)
(intcode-op-handler handler-entry)
tape pos)))
;; Now it's time to define all the operations we can do
;; Binary operations!!!
(define spec-binop '(in in out))
(define ((intcode-generic-binop op) cb tape pos lhs rhs dst)
(cb (list-set tape dst (op lhs rhs)) pos))
(intcode-register 1 spec-binop (intcode-generic-binop +))
(intcode-register 2 spec-binop (intcode-generic-binop *))
(define (bool->number b) (if b 1 0))
(intcode-register 7 spec-binop (intcode-generic-binop (compose bool->number <)))
(intcode-register 8 spec-binop (intcode-generic-binop (compose bool->number =)))
;; I/O time
(define current-input-channel (make-parameter (make-async-channel)))
(define current-output-channel (make-parameter (make-async-channel)))
(define instance (make-parameter '()))
(define (instance-log what)
(if (empty? (instance)) (void) (displayln (format "~a ~a" (instance) what))))
(define (intcode-input cb tape pos dst)
(define inp (async-channel-get (current-input-channel)))
(instance-log (list "input" inp))
(cb (list-set tape dst inp) pos))
(intcode-register 3 '(out) intcode-input)
(define (intcode-output cb tape pos src)
(instance-log (list "output" src))
(async-channel-put (current-output-channel) src)
(cb tape pos))
(intcode-register 4 '(in) intcode-output)
;; Jumps
(define ((intcode-generic-jump which) cb tape pos arg dst)
(cb tape (if (which arg) dst pos)))
(intcode-register 5 '(in in) (intcode-generic-jump (compose not zero?)))
(intcode-register 6 '(in in) (intcode-generic-jump zero?))
;; Exit
(define (intcode-exit cb tape pos)
(instance-log "exit")
(void))
(intcode-register 99 '() intcode-exit)
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(define (parse-input input)
(map string->number (string-split (string-trim input) ",")))
(define input (parse-input (file->string "input.7.txt")))
(define (intcode-eval-layer tape phase signal)
(parameterize ([current-input-channel (make-async-channel)]
[current-output-channel (make-async-channel)])
(begin
(async-channel-put (current-input-channel) phase)
(async-channel-put (current-input-channel) signal)
(intcode-eval tape)
(async-channel-get (current-output-channel)))))
(define initial-signal 0)
(define (intcode-eval-layers tape phases)
(foldl (lambda (phase signal)
(intcode-eval-layer tape phase signal))
initial-signal
phases))
;; Part 1
(apply max
(map (lambda (phases)
(intcode-eval-layers input phases))
(permutations (range 0 5))))
(define (list-rotate lst)
(cond
[(empty? list) '()]
[else `(,@(rest lst) ,(first lst))]))
(define (intcode-eval-layers/threaded tape phases first-signal)
(define channels (for/list ([_ phases]) (make-async-channel)))
(map (lambda (chan phase) (async-channel-put chan phase)) channels phases)
(define threads
(for/list ([chan-in channels]
[chan-out (list-rotate channels)]
[i (in-range (length channels))])
(parameterize ([current-input-channel chan-in]
[current-output-channel chan-out]
#|[instance i]|#)
(thread (lambda () (intcode-eval tape))))))
(async-channel-put (first channels) first-signal)
(map thread-wait threads)
(async-channel-get (first channels)))
;; Part 2
(apply max
(map (lambda (phases)
(intcode-eval-layers/threaded input phases initial-signal))
(permutations (range 5 10))))