1 files changed, 85 insertions, 0 deletions
diff --git a/racket/aoc2022/day-11/day-11.rkt b/racket/aoc2022/day-11/day-11.rkt
new file mode 100644
index 0000000..af7b4ee
--- /dev/null
+++ b/racket/aoc2022/day-11/day-11.rkt
@@ -0,0 +1,85 @@
+#lang racket
+(require threading)
+
+(struct monkey ([items #:mutable] operation modulus yes no))
+
+;; really don't feel like parsing the input today
+(define monkeys-list
+  (list (cons 0 (monkey '(97 81 57 57 91 61)
+                        (λ (n) (* n 7))
+                        11 5 6))
+        (cons 1 (monkey '(88 62 68 90)
+                        (λ (n) (* n 17))
+                        19 4 2))
+        (cons 2 (monkey '(74 87)
+                        (λ (n) (+ n 2))
+                        5 7 4))
+        (cons 3 (monkey '(53 81 60 87 90 99 75)
+                        (λ (n) (+ n 1))
+                        2 2 1))
+        (cons 4 (monkey '(57)
+                        (λ (n) (+ n 6))
+                        13 7 0))
+        (cons 5 (monkey '(54 84 91 55 59 72 75 70)
+                        (λ (n) (* n n))
+                        7 6 3))
+        (cons 6 (monkey '(95 79 79 68 78)
+                        (λ (n) (+ n 3))
+                        3 1 3))
+        (cons 7 (monkey '(61 97 67)
+                        (λ (n) (+ n 4))
+                        17 0 5))))
+
+(define monkey-lcm (~> monkeys-list (map (λ~> cdr monkey-modulus) _) (apply lcm _)))
+
+;; part 1
+(define monkeys-count-pt1 (make-hash))
+(define monkeys-hash-pt1 (make-hash monkeys-list))
+
+(for
+    ([rnd (in-range 20)])
+  (for
+      ([turn (inclusive-range 0 7)])
+    (match-define (monkey items op modulus yes no) (hash-ref monkeys-hash-pt1 turn))
+    (for ([i (in-list items)])
+      (define i* (quotient (op i) 3))
+      (define m (if (= 0 (modulo i* modulus)) yes no))
+      (match-define (monkey items* op* modulus* yes* no*) (hash-ref monkeys-hash-pt1 m))
+      (hash-update! monkeys-count-pt1 turn add1 0)
+      (hash-set! monkeys-hash-pt1
+                 m
+                 (monkey (append items* (list i*)) op* modulus* yes* no*)))
+    (hash-set! monkeys-hash-pt1 turn (monkey '() op modulus yes no))))
+
+(~> monkeys-count-pt1
+    hash->list
+    (sort _ > #:key cdr)
+    (take _ 2)
+    (map cdr _)
+    (apply * _))
+
+;; part 2
+(define monkeys-count-pt2 (make-hash))
+(define monkeys-hash-pt2 (make-hash monkeys-list))
+
+(for
+    ([rnd (in-range 10000)])
+  (for
+      ([turn (inclusive-range 0 7)])
+    (match-define (monkey items op modulus yes no) (hash-ref monkeys-hash-pt2 turn))
+    (for ([i (in-list items)])
+      (define i* (op i))
+      (define m (if (= 0 (modulo i* modulus)) yes no))
+      (match-define (monkey items* op* modulus* yes* no*) (hash-ref monkeys-hash-pt2 m))
+      (hash-update! monkeys-count-pt2 turn add1 0)
+      (hash-set! monkeys-hash-pt2
+                 m
+                 (monkey (append items* (list (remainder i* monkey-lcm))) op* modulus* yes* no*)))
+    (hash-set! monkeys-hash-pt2 turn (monkey '() op modulus yes no))))
+
+(~> monkeys-count-pt2
+    hash->list
+    (sort _ > #:key cdr)
+    (take _ 2)
+    (map cdr _)
+    (apply * _))
+\ No newline at end of file