start day16

2016/day16/input-b.rkt

@@ -0,0 +1,2 @@
+#lang reader "lang.rkt"
+35651584, 10010000000110000

2016/day16/input.rkt

@@ -0,0 +1,2 @@
+#lang reader "lang.rkt"
+272, 10010000000110000

2016/day16/lang.rkt

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+#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))))))
+  

2016/day16/test-b.rkt

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+#lang reader "lang.rkt"
+20, 10000

2016/day16/test.rkt

@@ -0,0 +1,2 @@
+#lang reader "lang.rkt"
+12, 110010110100