day 15 using structs; day 16 setup

2 files changed, 47 insertions, 15 deletions

diff --git a/2021/day-15/day-15.rkt b/2021/day-15/day-15.rkt
index 38c558a..e9101a6 100644
--- a/2021/day-15/day-15.rkt
+++ b/2021/day-15/day-15.rkt
@@ -3,6 +3,8 @@
          threading
          graph)
 
+(struct Point (x y) #:transparent)
+
 (define data
   (for/fold ([cells (hash)])
             ([row (in-lines (open-day 15 2021))]
@@ -11,18 +13,18 @@
               ([n (in-string row)]
                [y (in-naturals)])
       (hash-set cells
-                `(,x ,y)
+                (Point x y)
                 (~> n string string->number)))))
 
-(define x-max (~>> data hash-keys (map first) (apply max)))
-(define y-max (~>> data hash-keys (map second) (apply max)))
+(define x-max (~>> data hash-keys (map Point-x) (apply max)))
+(define y-max (~>> data hash-keys (map Point-y) (apply max)))
 
 (define (neighbors pt d)
-  (match-define (list x y) pt)
-  (~>> (list (list (add1 x) y)
-             (list (sub1 x) y)
-             (list x (add1 y))
-             (list x (sub1 y)))
+  (match-define (Point x y) pt)
+  (~>> (list (Point (add1 x) y)
+             (Point (sub1 x) y)
+             (Point x (add1 y))
+             (Point x (sub1 y)))
        (filter (curry hash-has-key? d))))
 
 (define (grid-graph d)
@@ -35,10 +37,10 @@
 ;; part 1
 (define (find-path-weight d)
   (define grid (grid-graph d))
-  (let-values ([(node-distances _) (dijkstra grid '(0 0))])
-    (define xm (~>> d hash-keys (map first) (apply max)))
-    (define ym (~>> d hash-keys (map second) (apply max)))
-    (hash-ref node-distances (list xm ym))))
+  (let-values ([(node-distances _) (dijkstra grid (Point 0 0))])
+    (define xm (~>> d hash-keys (map Point-x) (apply max)))
+    (define ym (~>> d hash-keys (map Point-y) (apply max)))
+    (hash-ref node-distances (Point xm ym))))
 
 (~> data
     find-path-weight
@@ -51,14 +53,14 @@
 (define (expand-data data)
   (for/fold ([cells (hash)])
             ([coord (in-list (hash-keys data))])
-    (match-define (list x y) coord)
+    (match-define (Point x y) coord)
     (for*/fold ([cells cells])
                ([n (in-range 5)]
                 [m (in-range 5)]
                 [val (in-value (hash-ref data coord))])
       (hash-set cells
-                (list (+ x (* n (add1 x-max)))
-                      (+ y (* m (add1 y-max))))
+                (Point (+ x (* n (add1 x-max)))
+                       (+ y (* m (add1 y-max))))
                 (sequence-ref nine-cycle (+ val n m -1))))))
 
 (~> data
diff --git a/2021/day-16/day-16.rkt b/2021/day-16/day-16.rkt
new file mode 100644
index 0000000..80c2a54
--- /dev/null
+++ b/2021/day-16/day-16.rkt
@@ -0,0 +1,30 @@
+#lang racket
+(require "../../jj-aoc.rkt"
+         threading)
+
+(define data
+  (~> (open-day 16 2021)
+      port->string
+      string-trim
+      string->list))
+
+(define (hex->bin h)
+  (match h
+    [#\0 '(0 0 0 0)]
+    [#\1 '(0 0 0 1)]
+    [#\2 '(0 0 1 0)]
+    [#\3 '(0 0 1 1)]
+    [#\4 '(0 1 0 0)]
+    [#\5 '(0 1 0 1)]
+    [#\6 '(0 1 1 0)]
+    [#\7 '(0 1 1 1)]
+    [#\8 '(1 0 0 0)]
+    [#\9 '(1 0 0 1)]
+    [#\A '(1 0 1 0)]
+    [#\B '(1 0 1 1)]
+    [#\C '(1 1 0 0)]
+    [#\D '(1 1 0 1)]
+    [#\E '(1 1 1 0)]
+    [#\F '(1 1 1 1)]))
+
+(map hex->bin data)
\ No newline at end of file