master
Matthew Butterick 5 years ago
parent c89b474616
commit b0238d1842

@ -1,57 +1,60 @@
#lang br #lang br
(require racket/file rackunit racket/generator) (require racket/file rackunit)
(define (string->ints str) (map string->number (string-split str #px",\\s*"))) (define (string->ints str) (map string->number (string-split str #px",\\s*")))
(define (string->regs str) (list->vector (string->ints str))) (define (string->regs str) (list->vector (string->ints str)))
(define ((binarize proc) x y) (if (proc x y) 1 0)) (define ((binarize proc) x y) (if (proc x y) 1 0))
(define (run str . inputs) (define (make-amp-thread program calling-thd)
(define regs (string->regs str)) (thread (λ ()
(define (reg-ref ptr) (vector-ref regs ptr)) (define regs (string->regs program))
(define (reg-set! ptr val) (vector-set! regs (reg-ref ptr) val)) (define (reg-ref ptr) (vector-ref regs ptr))
(define ip (open-input-string (string-join (map ~a inputs) " "))) (define (reg-set! ptr val) (vector-set! regs (reg-ref ptr) val))
(let/ec terminate (let/ec terminate
(let loop ([ptr 0]) (let loop ([ptr 0])
(match-define (list opcode mode-1 mode-2 mode-3) (match-define (list opcode mode-1 mode-2 mode-3)
(match (for/list ([c (in-string (~r (reg-ref ptr) #:min-width 5 #:pad-string "0"))]) (match (for/list ([c (in-string (~r (reg-ref ptr) #:min-width 5 #:pad-string "0"))])
(string->number (string c))) (string->number (string c)))
[(list d4 d3 d2 d1 d0) (cons (+ (* 10 d1) d0) [(list d4 d3 d2 d1 d0) (cons (+ (* 10 d1) d0)
(for/list ([mode-val (list d2 d3 d4)] (for/list ([mode-val (list d2 d3 d4)]
[offset '(1 2 3)]) [offset '(1 2 3)])
(λ (ptr) ((if (zero? mode-val) reg-ref values) (reg-ref (+ ptr offset))))))])) (λ (ptr) ((if (zero? mode-val) reg-ref values) (reg-ref (+ ptr offset))))))]))
(define next-ptr (define next-ptr
(match opcode (match opcode
[(or 1 2 7 8) ; 4-arity: add & multiply & compare [(or 1 2 7 8) ; 4-arity: add & multiply & compare
(reg-set! (+ ptr 3) ((match opcode (reg-set! (+ ptr 3) ((match opcode
[1 +] [1 +]
[2 *] [2 *]
[7 (binarize <)] [7 (binarize <)]
[8 (binarize =)]) (mode-1 ptr) (mode-2 ptr))) [8 (binarize =)]) (mode-1 ptr) (mode-2 ptr)))
(+ ptr 4)] (+ ptr 4)]
[(or 3 4) ; 2-arity: input & output [(or 3 4) ; 2-arity: input & output
(match opcode (match opcode
[3 (parameterize ([current-input-port ip]) [3 (reg-set! (+ ptr 1) (thread-receive))]
(reg-set! (+ ptr 1) (read)))] [4 (thread-send calling-thd (mode-1 ptr))])
[4 (println (mode-1 ptr))]) (+ ptr 2)]
(+ ptr 2)] [(or 5 6) ; 3-arity: jump
[(or 5 6) ; 3-arity: jump (if ((match opcode
(if ((match opcode [5 not]
[5 not] [6 values]) (zero? (mode-1 ptr)))
[6 values]) (zero? (mode-1 ptr))) (mode-2 ptr)
(mode-2 ptr) (+ ptr 3))]
(+ ptr 3))] [99 (terminate)]
[99 (terminate)] [_ (error "unknown-opcode" opcode)]))
[_ (error 'unknown-opcode)])) (loop next-ptr))))))
(loop next-ptr))))
(define-syntax-rule (last-output func) (define (make-amp-threads program phases)
(last (map string->number (string-split (with-output-to-string (λ () func)))))) (for/list ([phase (in-list (if (string? phases) (string->ints phases) phases))])
(define thd (make-amp-thread program (current-thread)))
(thread-send thd phase)
thd))
(define (thruster-signal program phases) (define (thruster-signal program phases)
(for/fold ([input 0]) (for/fold ([input 0])
([phase (in-list (if (string? phases) (string->ints phases) phases))]) ([amp (in-list (make-amp-threads program phases))])
(last-output (run program phase input)))) (thread-send amp input)
(thread-receive)))
(check-eq? (thruster-signal "3,15,3,16,1002,16,10,16,1,16,15,15,4,15,99,0,0" "4,3,2,1,0") 43210) (check-eq? (thruster-signal "3,15,3,16,1002,16,10,16,1,16,15,15,4,15,99,0,0" "4,3,2,1,0") 43210)
(check-eq? (thruster-signal "3,23,3,24,1002,24,10,24,1002,23,-1,23, (check-eq? (thruster-signal "3,23,3,24,1002,24,10,24,1002,23,-1,23,
@ -59,8 +62,34 @@
(check-eq? (thruster-signal "3,31,3,32,1002,32,10,32,1001,31,-2,31,1007,31,0,33, (check-eq? (thruster-signal "3,31,3,32,1002,32,10,32,1001,31,-2,31,1007,31,0,33,
1002,33,7,33,1,33,31,31,1,32,31,31,4,31,99,0,0,0" "1,0,4,3,2") 65210) 1002,33,7,33,1,33,31,31,1,32,31,31,4,31,99,0,0,0" "1,0,4,3,2") 65210)
(define amp-program (file->string "07.rktd"))
;; 1 ;; 1
(check-eq? (check-eq?
(apply max (for/list ([phases (in-permutations '(0 1 2 3 4))]) (apply max (for/list ([phases (in-permutations '(0 1 2 3 4))])
(thruster-signal (file->string "07.rktd") phases))) (thruster-signal amp-program phases)))
87138) 87138)
(define (thruster-signal-cycle program phases)
(for/fold ([input 0])
([amp (in-cycle (make-amp-threads program phases))]
#:break (not (thread-running? amp)))
(thread-send amp input)
(thread-receive)))
(check-eq?
(thruster-signal-cycle "3,26,1001,26,-4,26,3,27,1002,27,2,27,1,27,26,
27,4,27,1001,28,-1,28,1005,28,6,99,0,0,5" "9,8,7,6,5")
139629729)
(check-eq?
(thruster-signal-cycle "3,52,1001,52,-5,52,3,53,1,52,56,54,1007,54,5,55,1005,55,26,1001,54,
-5,54,1105,1,12,1,53,54,53,1008,54,0,55,1001,55,1,55,2,53,55,53,4,
53,1001,56,-1,56,1005,56,6,99,0,0,0,0,10" "9,7,8,5,6")
18216)
;; 2
(check-eq?
(apply max (for/list ([phases (in-permutations '(5 6 7 8 9))])
(thruster-signal-cycle amp-program phases)))
17279674)