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1 files changed, 48 insertions, 0 deletions

diff --git a/racket/aoc2021/day-19/day-19.rkt b/racket/aoc2021/day-19/day-19.rkt
new file mode 100644
index 0000000..4c6334d
--- /dev/null
+++ b/racket/aoc2021/day-19/day-19.rkt
@@ -0,0 +1,48 @@
+#lang racket
+(require "../../jj-aoc.rkt"
+         threading
+         racket/struct)
+
+(struct coord (x y z) #:transparent)
+
+(define (coord-broadcast f c1 c2)
+  (match-define (coord x1 y1 z1) c1)
+  (match-define (coord x2 y2 z2) c2)
+  (coord (f x1 x2) (f y1 y2) (f z1 z2)))
+
+(define (coord-reduce f c1 c2)
+  (foldl (λ (i1 i2 acc) (+ acc (f i1 i2))) 0 (struct->list c1) (struct->list c2)))
+
+(define coord-delta (curry coord-broadcast -))
+(define coord-sum (curry coord-broadcast +))
+(define coord-manhattan (curry coord-reduce (coord 0 0 0)))
+
+(define (create-scan-data d)
+  (for/list ([l (in-list d)])
+    (for/list ([pt (in-list (~> (string-split l "\n") rest))])
+      (~>> pt
+           (regexp-match #px"(-?\\d+),(-?\\d+),(-?\\d+)")
+           rest
+           (map string->number)
+           (apply coord)))))
+
+(define scanner-data (create-scan-data (~>> (open-day 19 2021) port->string (string-split _ "\n\n"))))
+
+(define (generate-rotations scanner)
+  (apply
+   map
+   list
+   (for*/list ([pt (in-list scanner)])
+     (match-define (coord x y z) pt)
+     (define orientations (list (list x y z) (list x z (- y)) (list x (- y) (- z)) (list x (- z) y)))
+     (append* (for/list ([o (in-list orientations)])
+                (match-define (list x* y* z*) o)
+                (list (list x y z)
+                      (list (- x) z y)
+                      (list z (- y) x)
+                      (list y x (- z))
+                      (list (- y) (- z) x)))))))
+
+(define (find-overlaps scan1 scan2)
+  (for/list ([rotation (in-permutations scan2)])
+    (map coord-sum scan1 rotation)))