You cannot select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
This repo is archived. You can view files and clone it, but cannot push or open issues/pull-requests.
aoc-racket/2016/day16/lang.rkt

39 lines
1017 B
Racket

#lang br/quicklang ;; http://adventofcode.com/2016/day/16
(require openssl/md5)
(provide read-syntax
(rename-out [mb #%module-begin]))
(define (read-syntax path port)
(strip-bindings
#`(module mod "lang.rkt"
#,@(string-split (string-trim (port->string port)) ", "))))
(define-macro (mb SIZE INIT)
#'(#%module-begin
(display (list->string (checksum (fill-disk (string->list INIT) (string->number SIZE)))))))
(define (dragonize cs)
(append cs '(#\0)
(for/list ([c (in-list (reverse cs))])
(if (eqv? c #\1)
#\0
#\1))))
(define (fill-disk init size)
(let loop ([cs init])
(if (>= (length cs) size)
(take cs size)
(loop (dragonize cs)))))
(require sugar/list)
(define (checksum cs)
(let loop ([cs cs])
(if (odd? (length cs))
cs
(loop
(for/list ([match (in-list (slice-at cs 2))])
(if (member match '((#\0 #\0) (#\1 #\1)))
#\1
#\0))))))