d13

2017/d13/main.rkt

@@ -0,0 +1,25 @@
+#lang reader "../aoc-lang.rkt"
+(require (for-syntax racket/string racket/sequence) racket/dict)
+(provide (rename-out [#%mb #%module-begin]) ★ ★★)
+
+(define-macro (#%mb (STARS) (DEPTH: RANGE) ...)
+  (with-pattern ([(DEPTH ...)
+                  (for/list ([id (in-syntax #'(DEPTH: ...))])
+                    (string->number (string-trim (symbol->string (syntax->datum id)) ":")))])
+    #'(#%module-begin (STARS '(DEPTH ...) '(RANGE ...)))))
+
+(define (caught? depth range [delay 0])
+  (zero? (modulo (+ depth delay) (* 2 (sub1 range)))))
+
+(define (★ ds rs)
+  (for/sum ([d (in-list ds)]
+            [r (in-list rs)]
+            #:when (caught? d r))
+    (* d r)))
+
+(define (★★ ds rs)
+  (for/first ([delay (in-naturals)]
+              #:unless (for/or ([d (in-list ds)]
+                                [r (in-list rs)])
+                         (caught? d r delay)))
+    delay))

2017/d13/star1.rkt

@@ -0,0 +1,44 @@
+#lang reader "main.rkt" ★ ; 1612
+0: 3
+1: 2
+2: 4
+4: 6
+6: 4
+8: 6
+10: 5
+12: 6
+14: 8
+16: 8
+18: 8
+20: 6
+22: 12
+24: 8
+26: 8
+28: 10
+30: 9
+32: 12
+34: 8
+36: 12
+38: 12
+40: 12
+42: 14
+44: 14
+46: 12
+48: 12
+50: 12
+52: 12
+54: 14
+56: 12
+58: 14
+60: 14
+62: 14
+64: 14
+70: 10
+72: 14
+74: 14
+76: 14
+78: 14
+82: 14
+86: 17
+88: 18
+96: 26

2017/d13/star2.rkt

@@ -0,0 +1,44 @@
+#lang reader "main.rkt" ★★ ; 3907994
+0: 3
+1: 2
+2: 4
+4: 6
+6: 4
+8: 6
+10: 5
+12: 6
+14: 8
+16: 8
+18: 8
+20: 6
+22: 12
+24: 8
+26: 8
+28: 10
+30: 9
+32: 12
+34: 8
+36: 12
+38: 12
+40: 12
+42: 14
+44: 14
+46: 12
+48: 12
+50: 12
+52: 12
+54: 14
+56: 12
+58: 14
+60: 14
+62: 14
+64: 14
+70: 10
+72: 14
+74: 14
+76: 14
+78: 14
+82: 14
+86: 17
+88: 18
+96: 26

2017/d13/test1.rkt

@@ -0,0 +1,5 @@
+#lang reader "main.rkt" ★ ; 24
+0: 3
+1: 2
+4: 4
+6: 4

2017/d13/test2.rkt

@@ -0,0 +1,5 @@
+#lang reader "main.rkt" ★★ 
+0: 3
+1: 2
+4: 4
+6: 4