blob: af7b4ee643cd0c0b78734c30bb3d18e848089499 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
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 * _))
|
