2021 solutions

master
Matthew Butterick 12 months ago
parent 4d5f19b410
commit af8752d29e
  1. 20
      2021/01.rkt
  2. 2000
      2021/01.rktd
  3. 32
      2021/02.rkt
  4. 1000
      2021/02.rktd
  5. 40
      2021/03.rkt
  6. 1000
      2021/03.rktd
  7. 43
      2021/04.rkt
  8. 601
      2021/04.rktd
  9. 38
      2021/05.rkt
  10. 500
      2021/05.rktd
  11. 18
      2021/06.rkt
  12. 1
      2021/06.rktd
  13. 13
      2021/07.rkt
  14. 1
      2021/07.rktd
  15. 71
      2021/08.rkt
  16. 200
      2021/08.rktd
  17. 36
      2021/09.rkt
  18. 100
      2021/09.rktd
  19. 43
      2021/10.rkt
  20. 102
      2021/10.rktd
  21. 52
      2021/11.rkt
  22. 10
      2021/11.rktd
  23. 38
      2021/12.rkt
  24. 23
      2021/12.rktd
  25. 40
      2021/13.rkt
  26. 865
      2021/13.rktd
  27. 54
      2021/14.rkt
  28. 102
      2021/14.rktd
  29. 59
      2021/15.rkt
  30. 100
      2021/15.rktd

@ -0,0 +1,20 @@
#lang br
(require racket/file rackunit)
(define depths (map string->number (file->lines "01.rktd")))
(define (positive-deltas depths)
(filter positive?
(for/list ([d1 (in-list depths)]
[d2 (in-list (cdr depths))])
(- d2 d1))))
(check-equal? (length (positive-deltas depths)) 1167)
(define (trios depths)
(for/list ([d1 (in-list depths)]
[d2 (in-list (cdr depths))]
[d3 (in-list (cddr depths))])
(+ d1 d2 d3)))
(check-equal? (length (positive-deltas (trios depths))) 1130)

File diff suppressed because it is too large Load Diff

@ -0,0 +1,32 @@
#lang br
(require racket/file sugar/list rackunit)
(define instructions
(slice-at (for/list ([datum (in-port read (open-input-file "02.rktd"))])
datum) 2))
(define (solve matcher)
(for/fold ([pos 0]
[depth 0]
[aim 0]
#:result (* pos depth))
([i (in-list instructions)])
(matcher pos depth aim i)))
(define (solve-1)
(solve (λ (pos depth aim i)
(match i
[(list 'forward amt) (values (+ pos amt) depth aim)]
[(list 'down amt) (values pos (+ depth amt) aim)]
[(list 'up amt) (values pos (- depth amt) aim)]))))
(check-equal? (solve-1) 1488669)
(define (solve-2)
(solve (λ (pos depth aim i)
(match i
[(list 'forward amt) (values (+ pos amt) (+ depth (* aim amt)) aim)]
[(list 'down amt) (values pos depth (+ aim amt))]
[(list 'up amt) (values pos depth (- aim amt))]))))
(check-equal? (solve-2) 1176514794)

File diff suppressed because it is too large Load Diff

@ -0,0 +1,40 @@
#lang br
(require racket/file rackunit)
(define lines (map string->list (file->lines "03.rktd")))
(define (digit-columns lines) (apply map list lines))
(define (most-common-digit chars)
(define zeroes (count (λ (c) (char=? c #\0)) chars))
(define most-threshold (/ (length chars) 2))
(cond
[(= zeroes most-threshold) #f]
[(> zeroes most-threshold) #\0]
[else #\1]))
(define (least-common-digit chars)
(match (most-common-digit chars)
[#false #false]
[#\0 #\1]
[_ #\0]))
(define (chars->binary-number chars)
(string->number (list->string chars) 2))
(define gamma-rate (chars->binary-number (map most-common-digit (digit-columns lines))))
(define epsilon-rate (chars->binary-number (map least-common-digit (digit-columns lines))))
(check-equal? (* gamma-rate epsilon-rate) 4174964)
(define (find-digit proc default)
(for/fold ([lines lines]
#:result (chars->binary-number (car lines)))
([i (in-range (length (car lines)))]
#:break (= (length lines) 1))
(define target (or (proc (list-ref (digit-columns lines) i)) default))
(filter (λ (line) (char=? (list-ref line i) target)) lines)))
(define oxygen-rate (find-digit most-common-digit #\1))
(define co2-rate (find-digit least-common-digit #\0))
(check-equal? (* oxygen-rate co2-rate) 4474944)

File diff suppressed because it is too large Load Diff

@ -0,0 +1,43 @@
#lang br
(require racket/file sugar rackunit)
(define lines (file->lines "04.rktd"))
(define numbers-to-draw (map string->number (string-split (string-replace (car lines) "," " "))))
(define boards
(map list->vector (slice-at (map string->number (string-split (string-join (cdr lines)))) 25)))
(define winning-lines
(let ()
(define rows '((0 1 2 3 4) (5 6 7 8 9) (10 11 12 13 14) (15 16 17 18 19) (20 21 22 23 24)))
(define cols (apply map list rows))
(append rows cols)))
(define (board-wins board)
(for/or ([winning-line winning-lines])
(for/and ([idx winning-line])
(eq? (vector-ref board idx) #true))))
(define (run-game boards)
(for*/fold ([boards boards]
[winners null]
#:result (reverse winners))
([number numbers-to-draw]
#:break (empty? boards))
(for ([board boards])
(define pos-of-number (vector-member number board))
(when pos-of-number
(vector-set! board pos-of-number #true)))
(define-values (new-winners losers) (partition board-wins boards))
(values losers (append (for/list ([winner new-winners])
(cons number winner)) winners))))
(define (calc-score res)
(match res
[(cons last-number board) (* last-number (apply + (filter number? (vector->list board))))]))
(define results (run-game boards))
(check-equal? (calc-score (first results)) 64084)
(check-equal? (calc-score (last results)) 12833)

@ -0,0 +1,601 @@
27,14,70,7,85,66,65,57,68,23,33,78,4,84,25,18,43,71,76,61,34,82,93,74,26,15,83,64,2,35,19,97,32,47,6,51,99,20,77,75,56,73,80,86,55,36,13,95,52,63,79,72,9,10,16,8,69,11,50,54,81,22,45,1,12,88,44,17,62,0,96,94,31,90,39,92,37,40,5,98,24,38,46,21,30,49,41,87,91,60,48,29,59,89,3,42,58,53,67,28
31 23 52 26 8
27 89 37 80 46
97 19 63 34 79
13 59 45 12 73
42 25 22 6 39
27 71 24 3 0
79 42 32 72 62
99 52 11 92 33
38 22 16 44 39
35 26 76 49 58
39 19 82 53 57
52 98 69 77 23
1 40 18 66 83
34 85 28 48 16
15 93 38 96 27
74 50 88 84 99
34 2 11 25 17
57 4 19 83 1
59 77 42 36 33
73 22 23 37 55
98 91 56 84 78
45 21 24 83 40
46 58 8 67 4
33 97 55 7 86
2 68 64 27 69
68 29 14 49 26
4 21 87 71 32
58 5 17 46 93
45 96 8 83 2
78 91 9 20 42
49 81 19 48 37
38 23 45 82 92
93 99 67 66 42
40 74 25 56 16
21 47 26 75 61
53 66 72 30 34
55 82 77 6 92
60 56 8 22 88
5 71 49 29 74
28 2 32 84 73
52 31 24 68 41
48 82 19 29 65
51 91 97 39 80
3 55 43 40 38
20 89 53 45 75
29 74 19 89 18
32 88 93 46 63
91 4 94 64 5
57 54 49 36 40
97 81 39 77 1
7 57 94 84 39
92 3 28 15 75
88 45 65 81 63
86 4 89 37 71
8 13 66 42 85
60 66 35 47 98
96 27 40 51 39
3 64 25 28 74
58 17 97 59 29
95 31 18 44 37
3 31 97 85 71
79 82 22 61 98
87 14 17 66 75
36 89 88 83 63
44 8 81 25 48
73 84 28 90 94
25 19 44 10 23
8 59 17 9 93
20 77 97 64 6
98 82 27 70 91
18 51 16 99 2
58 22 89 13 19
39 66 91 8 32
49 24 85 94 42
45 70 10 86 4
23 81 66 13 34
25 80 97 5 42
79 35 2 78 9
0 6 91 94 45
21 90 76 50 56
50 92 2 96 75
85 82 80 97 31
61 35 55 27 56
74 42 9 29 90
86 15 88 47 1
18 20 54 92 62
45 22 32 61 75
1 38 50 81 42
82 4 21 77 65
27 51 56 39 48
36 10 62 28 70
94 99 34 54 6
15 1 41 13 12
92 52 2 63 82
90 64 29 69 32
23 77 33 90 17
45 78 5 67 28
57 73 89 81 21
49 64 37 15 14
7 59 4 43 16
81 92 25 28 90
93 72 43 94 26
24 9 13 74 10
21 2 36 32 51
87 97 55 86 71
82 71 99 17 90
69 95 65 55 10
9 92 39 62 78
59 13 61 24 44
8 31 58 0 57
17 83 55 99 27
79 4 33 76 7
81 43 44 49 72
2 48 97 20 77
47 60 35 16 63
93 95 94 1 98
61 57 84 55 22
85 40 65 46 59
21 15 63 77 7
13 99 49 3 96
8 21 14 45 41
65 63 82 62 28
91 44 22 79 96
20 75 86 3 26
74 11 42 59 36
5 52 43 92 99
46 63 10 45 81
13 66 21 32 89
25 28 96 40 88
27 18 31 73 34
3 26 43 32 36
68 87 67 65 99
73 61 20 90 7
21 52 2 82 10
58 49 56 16 80
97 25 93 63 32
87 14 5 22 76
89 92 91 3 51
0 24 95 69 20
96 11 10 1 55
95 86 44 75 70
59 76 45 2 99
1 34 71 81 41
87 14 33 84 96
8 38 9 82 68
27 71 70 75 76
25 87 2 79 96
20 88 50 37 32
48 94 63 86 22
15 6 34 78 59
30 89 51 31 77
74 10 86 71 84
29 54 58 44 5
11 90 26 50 63
64 62 20 40 46
37 9 46 23 31
68 21 25 36 90
17 33 6 50 30
11 89 20 47 60
26 59 34 62 77
84 52 40 97 7
88 30 42 58 94
64 10 2 90 83
44 35 77 91 47
14 74 9 78 53
86 14 0 39 24
87 69 58 8 73
88 74 27 40 51
63 54 55 93 61
16 66 15 21 48
43 70 9 81 42
36 54 99 34 95
98 19 90 25 44
69 56 18 77 49
58 16 67 75 57
36 44 14 98 23
31 5 83 46 3
45 21 41 11 60
33 81 88 92 65
13 51 48 59 71
12 5 70 87 32
42 18 90 73 88
68 29 76 38 55
67 62 15 77 34
39 27 51 54 19
87 8 92 93 88
77 54 15 1 43
35 97 26 21 29
13 46 96 69 47
51 38 91 32 63
73 99 30 15 16
42 58 21 88 44
45 13 27 68 9
36 6 81 53 5
78 76 11 60 1
57 76 50 78 31
45 42 68 53 16
9 88 89 19 21
96 61 97 69 34
98 87 33 82 0
4 16 89 57 64
46 75 77 65 23
71 42 96 52 38
1 21 93 0 35
59 80 53 36 58
97 62 35 1 88
98 60 17 45 94
12 43 65 23 19
71 52 3 40 59
50 76 61 20 22
92 65 38 93 13
55 26 10 46 29
85 23 19 74 34
60 14 27 36 18
53 4 52 49 17
99 56 93 70 28
25 0 77 80 57
91 50 72 76 23
53 58 95 78 59
75 85 90 44 9
30 8 5 60 6
28 35 59 70 96
20 99 98 81 79
94 78 27 71 4
7 34 43 46 51
93 65 22 69 33
92 49 75 35 11
58 39 62 86 83
64 4 76 48 82
74 1 56 95 31
1 78 98 90 55
80 14 36 99 7
85 8 10 9 92
76 11 40 70 62
43 53 74 35 58
46 78 35 28 49
84 73 65 25 34
40 59 66 36 67
16 22 29 0 45
20 56 39 88 91
32 58 35 25 79
78 94 57 38 14
89 87 68 48 76
7 67 40 51 33
95 31 43 93 92
38 21 82 31 23
54 16 77 37 42
73 99 7 34 90
71 26 5 91 52
22 27 47 85 62
2 86 28 37 55
1 82 9 36 31
52 98 89 30 60
13 17 63 38 57
73 50 42 20 12
56 3 67 62 35
59 39 19 22 27
21 58 57 41 54
75 13 82 50 32
23 5 99 66 10
7 19 45 66 78
38 57 40 73 87
58 30 99 53 83
64 1 8 56 95
70 77 16 18 82
72 83 95 37 35
54 59 92 21 79
7 81 86 29 41
52 99 42 57 71
3 15 75 34 77
7 70 5 69 4
34 60 40 73 6
74 54 67 32 38
93 62 17 51 86
57 88 99 3 16
42 74 11 34 7
82 47 71 31 58
69 23 43 4 64
32 19 98 93 41
63 97 8 85 48
63 54 34 38 86
4 27 15 49 0
61 77 53 98 74
62 23 88 97 37
93 28 25 50 13
56 82 41 27 79
23 31 64 7 65
52 98 93 16 57
88 49 10 11 62
43 95 53 51 83
41 10 87 54 86
19 22 13 40 17
37 27 45 29 63
83 85 81 90 7
57 88 47 66 56
67 44 54 88 89
20 46 61 28 92
86 49 60 83 95
42 78 97 51 96
11 62 4 26 31
18 68 87 26 70
62 84 11 33 90
0 45 66 83 6
20 19 27 44 55
52 8 5 7 3
54 94 88 76 92
13 98 22 33 26
95 62 53 81 24
29 69 15 87 25
61 40 84 90 93
7 31 3 28 46
20 51 21 18 38
30 92 39 70 61
27 88 35 96 74
23 5 66 11 42
40 61 90 57 54
41 14 99 62 59
92 10 48 81 52
22 29 77 18 87
31 79 25 94 13
17 26 44 98 57
74 83 51 14 11
76 91 96 64 33
43 45 92 72 27
66 3 28 20 40
88 82 44 71 55
83 47 51 76 24
86 19 42 34 99
30 31 87 48 62
98 53 68 9 21
3 31 6 41 61
24 77 81 96 44
78 73 1 98 11
40 80 27 65 92
62 67 2 30 10
78 46 50 65 56
84 16 32 58 86
22 12 54 99 35
9 43 55 10 94
66 81 59 92 76
78 3 55 23 83
13 42 94 91 22
14 37 31 67 71
8 61 57 34 43
74 50 0 39 65
78 16 13 91 34
14 74 86 3 97
12 89 58 65 51
29 57 48 44 93
95 1 42 39 92
93 96 16 85 25
59 3 70 19 17
21 84 58 38 86
57 10 35 95 79
81 44 73 63 9
22 1 96 7 93
40 49 2 4 66
87 21 17 32 48
44 28 42 99 26
69 8 85 86 75
21 31 37 87 28
89 43 74 83 57
95 29 92 88 35
94 25 97 81 50
15 19 73 45 63
92 62 67 95 57
30 8 4 39 64
99 31 70 63 96
25 53 24 93 35
34 51 82 91 28
41 30 20 56 46
16 32 98 60 35
67 9 43 42 88
78 90 71 5 29
49 31 37 63 18
80 40 88 5 62
3 6 74 71 97
19 58 63 59 38
50 64 34 68 45
25 30 21 33 83
10 65 67 17 50
21 51 18 68 59
29 78 77 99 76
62 35 96 7 95
82 53 42 49 69
74 65 89 6 1
18 30 72 75 24
60 50 52 55 82
68 99 4 61 22
9 37 84 57 87
96 85 56 72 2
9 38 98 12 4
34 45 74 97 86
18 94 64 70 68
91 41 58 39 66
34 13 26 80 29
0 4 21 60 90
39 73 12 2 19
64 44 61 88 45
59 50 8 91 49
34 85 55 2 75
10 15 89 12 63
90 29 87 73 71
38 17 84 45 9
97 98 77 23 61
47 43 22 58 1
63 44 2 94 99
33 81 51 49 13
38 86 42 91 23
7 67 68 39 84
4 26 12 38 41
43 16 88 71 99
50 24 19 77 98
23 73 44 10 51
56 42 30 52 59
57 16 9 62 27
26 65 56 10 82
0 74 78 12 99
77 18 38 5 37
7 60 40 90 23
14 69 18 51 8
21 79 60 36 12
68 44 59 45 16
90 50 85 25 70
91 31 30 54 26
24 40 51 72 63
31 60 62 25 96
9 44 35 28 91
97 4 34 81 2
61 68 94 52 86
0 57 95 88 94
36 38 25 35 19
13 6 8 61 98
45 85 86 69 97
41 32 7 15 59
41 82 19 29 34
44 96 6 91 76
69 21 32 94 98
4 10 88 30 2
8 74 56 65 99
36 91 73 15 54
62 55 40 27 44
11 60 95 61 46
31 32 21 41 35
74 86 83 89 79
2 96 94 82 68
39 83 49 30 15
62 11 86 99 59
51 80 12 72 58
87 66 98 53 29
44 71 18 63 85
11 75 60 66 13
36 9 94 57 8
10 12 32 3 86
4 29 54 70 21
27 33 76 83 67
77 29 65 39 44
52 34 25 93 64
35 4 57 92 84
41 51 88 96 0
21 91 82 3 26
23 8 36 20 73
54 39 60 34 57
49 99 97 69 43
41 93 95 80 63
73 77 4 9 22
17 33 15 86 79
38 16 99 98 30
64 92 76 50 68
83 85 52 87 88
57 53 13 36 76
7 10 91 3 22
8 84 56 73 59
62 80 85 38 33
68 97 47 14 96
36 8 98 43 70
85 95 31 1 51
33 41 78 89 56
76 16 15 34 82
12 18 39 4 3
98 49 41 30 95
68 89 81 48 84
15 19 90 66 14
32 1 88 34 64
73 65 6 20 86
22 18 13 74 34
75 4 60 88 46
25 97 54 94 91
42 67 40 11 81
5 12 49 48 15
82 91 18 73 57
97 50 34 16 66
29 43 81 20 15
19 44 85 4 32
90 58 39 53 42
50 53 83 10 0
93 16 84 23 13
89 63 75 69 51
65 35 67 56 70
4 37 29 47 38

@ -0,0 +1,38 @@
#lang br
(require racket/file sugar rackunit racket/set)
(define lines (map (λ (s) (map (λ (s2) (define ints (map string->number (string-split s2 ",")))
(+ (first ints) (* +i (second ints)))) (string-split s " -> "))) (file->lines "05.rktd")))
(define (Line-not-diagonal line)
(match line
[(list left right) (or (= (real-part left) (real-part right)) (= (imag-part left) (imag-part right)))]))
;; why does make-polar cause the solution to run faster?
;; both functions create an imaginary number
;; make-polar is slower to create the numbers (because it has to call trig functions)
;; but storing the polar numbers with frequency-hash is much faster
;; using inexact coefficients makes make-rectangular go faster
;; but still not as fast as make-polar
(define go-fast? #true)
(define imag-func (if go-fast? make-polar make-rectangular))
(define (expand line)
(match-define (list x1 x2) (map real-part line))
(match-define (list y1 y2) (map imag-part line))
(cond
[(= x1 x2)
(for/list ([i (in-range (apply min (list y1 y2)) (add1 (apply max (list y1 y2))))])
(imag-func x1 i))]
[(= y1 y2)
(for/list ([i (in-range (apply min (list x1 x2)) (add1 (apply max (list x1 x2))))])
(imag-func i y1))]
[else (for/list ([x (in-range x1 ((if (> x1 x2) sub1 add1) x2) (if (> x1 x2) -1 1))]
[y (in-range y1 ((if (> y1 y2) sub1 add1) y2) (if (> y1 y2) -1 1))])
(imag-func x y))]))
(define (calc-result points)
(length (filter (λ (x) (>= x 2)) (hash-values (time (frequency-hash points))))))
(check-equal? (calc-result (append-map expand (filter Line-not-diagonal lines))) 6113)
(check-equal? (calc-result (append-map expand lines)) 20373)

@ -0,0 +1,500 @@
309,347 -> 309,464
425,687 -> 300,687
226,766 -> 885,107
681,618 -> 921,378
968,54 -> 38,984
35,341 -> 321,627
493,485 -> 632,485
908,183 -> 110,981
677,378 -> 677,231
703,378 -> 703,536
179,581 -> 429,331
339,133 -> 664,458
212,680 -> 212,136
251,699 -> 858,699
163,725 -> 163,22
70,226 -> 97,226
968,119 -> 954,119
551,551 -> 415,551
768,167 -> 546,167
125,302 -> 155,332
640,201 -> 341,201
757,791 -> 757,736
406,570 -> 418,558
250,919 -> 976,193
570,362 -> 304,96
463,973 -> 463,337
322,199 -> 322,73
141,186 -> 141,906
964,940 -> 964,743
99,461 -> 15,461
255,856 -> 255,194
650,293 -> 650,136
89,98 -> 969,978
974,977 -> 37,40
641,795 -> 985,795
441,972 -> 441,427
18,942 -> 943,17
166,167 -> 617,167
182,146 -> 790,146
88,854 -> 928,14
537,38 -> 233,38
786,562 -> 867,562
251,102 -> 147,102
551,373 -> 672,252
915,713 -> 791,589
28,373 -> 28,651
463,365 -> 396,365
349,948 -> 737,948
246,860 -> 84,860
334,817 -> 866,285
880,958 -> 641,719
229,203 -> 740,714
39,220 -> 575,756
899,383 -> 275,383
49,952 -> 774,952
384,42 -> 581,42
11,731 -> 522,731
194,638 -> 679,153
922,279 -> 922,398
589,579 -> 709,579
97,716 -> 244,716
769,923 -> 769,189
636,567 -> 866,337
413,925 -> 729,925
581,524 -> 89,32
970,217 -> 851,217
716,373 -> 122,967
606,785 -> 191,785
322,432 -> 706,432
788,911 -> 788,889
904,917 -> 904,862
889,351 -> 796,351
508,18 -> 508,165
859,187 -> 879,187
531,409 -> 562,378
914,97 -> 233,778
194,191 -> 194,592
620,674 -> 55,109
194,973 -> 863,973
679,940 -> 679,296
836,108 -> 700,108
861,376 -> 585,376
166,299 -> 166,141
847,377 -> 847,217
872,972 -> 872,413
28,872 -> 28,695
876,152 -> 108,920
487,536 -> 697,536
30,28 -> 982,980
834,503 -> 834,586
927,459 -> 339,459
87,809 -> 770,126
24,973 -> 981,16
185,383 -> 185,13
850,328 -> 541,19
399,111 -> 742,111
703,305 -> 458,305
571,889 -> 803,657
356,697 -> 364,697
847,160 -> 108,899
170,954 -> 137,954
927,120 -> 897,150
687,662 -> 507,662
762,259 -> 762,951
90,612 -> 647,55
114,437 -> 483,68
138,269 -> 638,269
720,947 -> 29,947
563,52 -> 360,52
665,953 -> 187,475
283,855 -> 283,744
120,284 -> 120,319
935,422 -> 349,422
372,858 -> 372,779
68,768 -> 814,22
206,400 -> 22,400
72,954 -> 977,49
861,557 -> 794,557
893,654 -> 893,132
306,364 -> 697,364
828,165 -> 695,165
122,57 -> 986,921
509,470 -> 608,470
794,730 -> 520,456
291,305 -> 525,71
648,530 -> 92,530
329,173 -> 329,343
960,941 -> 133,114
256,523 -> 369,523
433,379 -> 195,379
199,783 -> 821,783
974,205 -> 299,205
200,400 -> 27,573
294,175 -> 294,493
320,20 -> 320,393
274,85 -> 969,780
112,73 -> 112,969
371,381 -> 121,631
942,906 -> 46,906
663,742 -> 208,287
422,258 -> 422,356
884,283 -> 859,283
750,142 -> 710,142
823,454 -> 642,273
296,366 -> 296,245
518,615 -> 852,949
74,513 -> 655,513
850,77 -> 850,950
985,980 -> 33,28
16,982 -> 979,19
265,234 -> 849,234
303,408 -> 229,334
344,63 -> 932,651
417,597 -> 548,597
729,361 -> 245,845
888,156 -> 80,964
215,29 -> 411,225
762,108 -> 115,108
63,855 -> 875,43
398,382 -> 874,858
419,78 -> 419,417
263,553 -> 131,553
766,399 -> 584,399
778,126 -> 226,678
580,781 -> 580,401
623,506 -> 966,506
364,723 -> 364,349
834,667 -> 177,10
402,515 -> 402,493
924,50 -> 22,952
64,826 -> 64,470
199,694 -> 145,694
893,900 -> 20,27
850,834 -> 725,959
47,573 -> 575,45
71,287 -> 71,296
796,728 -> 796,442
88,700 -> 726,700
230,332 -> 412,514
618,284 -> 618,661
221,738 -> 817,142
149,38 -> 474,38
563,331 -> 441,331
219,187 -> 522,187
300,341 -> 300,633
228,305 -> 70,463
396,875 -> 22,875
533,116 -> 519,116
257,781 -> 257,443
181,236 -> 181,822
10,13 -> 986,989
59,290 -> 753,984
121,89 -> 121,827
958,233 -> 653,233
685,641 -> 685,322
167,124 -> 446,403
246,170 -> 77,339
503,189 -> 503,72
666,182 -> 824,340
825,675 -> 629,479
967,915 -> 967,785
749,403 -> 92,403
950,217 -> 950,391
356,872 -> 514,872
279,900 -> 138,900
114,284 -> 502,672
700,792 -> 32,124
252,783 -> 806,229
557,215 -> 557,103
35,29 -> 963,957
650,285 -> 23,912
669,191 -> 446,414
66,283 -> 66,37
564,250 -> 175,250
425,611 -> 425,964
662,224 -> 707,224
599,979 -> 599,873
402,886 -> 402,979
329,181 -> 329,964
120,891 -> 685,326
788,438 -> 788,460
140,939 -> 338,939
496,343 -> 327,343
749,151 -> 749,339
181,527 -> 181,455
61,949 -> 966,44
138,262 -> 894,262
192,146 -> 801,146
301,405 -> 765,405
938,235 -> 938,55
543,958 -> 320,958
54,982 -> 867,169
66,147 -> 702,783
839,419 -> 97,419
519,879 -> 519,707
159,255 -> 159,787
258,897 -> 968,897
427,10 -> 427,62
782,750 -> 782,960
878,742 -> 785,649
171,74 -> 883,74
220,184 -> 910,874
696,984 -> 696,512
175,753 -> 303,753
666,515 -> 45,515
886,101 -> 14,973
121,823 -> 154,823
63,976 -> 987,52
480,478 -> 167,791
757,338 -> 757,719
593,286 -> 542,286
989,602 -> 989,135
793,857 -> 712,857
65,976 -> 843,198
729,334 -> 106,957
102,234 -> 42,294
830,223 -> 267,223
800,590 -> 921,590
526,38 -> 863,38
770,719 -> 65,14
317,267 -> 541,267
653,697 -> 653,720
506,532 -> 483,555
564,387 -> 205,387
971,669 -> 971,966
421,905 -> 421,264
506,85 -> 407,85
435,863 -> 230,863
945,133 -> 694,133
604,921 -> 604,168
66,677 -> 499,244
300,551 -> 893,551
836,228 -> 836,631
29,208 -> 443,208
546,584 -> 148,584
855,904 -> 855,315
636,694 -> 852,478
399,252 -> 399,170
46,596 -> 46,789
919,211 -> 201,929
662,983 -> 545,866
22,913 -> 908,27
441,605 -> 94,952
190,257 -> 769,836
700,395 -> 861,556
562,620 -> 562,687
34,165 -> 603,734
372,302 -> 585,302
71,857 -> 588,340
956,566 -> 738,784
778,610 -> 74,610
331,640 -> 346,655
274,473 -> 274,691
646,142 -> 144,142
911,971 -> 618,971
233,341 -> 233,505
467,990 -> 41,990
633,739 -> 57,163
585,405 -> 905,405
320,449 -> 320,628
44,738 -> 44,293
67,267 -> 770,970
933,155 -> 765,323
383,879 -> 896,366
130,986 -> 435,986
264,863 -> 979,148
114,721 -> 725,110
546,949 -> 546,790
762,42 -> 67,42
443,985 -> 245,985
689,803 -> 126,803
496,702 -> 943,255
955,963 -> 117,125
686,411 -> 979,704
226,256 -> 226,352
889,683 -> 889,437
47,161 -> 545,161
450,283 -> 450,469
461,338 -> 461,695
808,777 -> 808,962
902,459 -> 902,744
793,703 -> 158,68
100,919 -> 69,919
912,785 -> 331,204
712,609 -> 712,512
268,762 -> 268,355
972,667 -> 974,667
647,647 -> 164,647
589,180 -> 589,644
836,258 -> 376,718
676,977 -> 211,977
626,608 -> 874,360
271,911 -> 324,858
182,374 -> 182,347
14,989 -> 985,18
461,462 -> 956,957
82,79 -> 974,971
607,478 -> 607,147
898,76 -> 582,392
326,31 -> 683,31
768,47 -> 768,348
35,386 -> 185,386
803,391 -> 803,932
879,486 -> 879,658
183,39 -> 183,855
431,467 -> 499,399
434,306 -> 304,436
774,618 -> 521,618
364,426 -> 364,457
44,849 -> 791,102
70,850 -> 276,850
181,838 -> 181,736
574,18 -> 574,784
103,613 -> 537,179
34,218 -> 115,299
808,777 -> 636,777
483,112 -> 483,939
15,790 -> 15,253
433,427 -> 742,427
829,947 -> 895,947
361,180 -> 860,180
124,499 -> 124,615
879,712 -> 745,712
16,12 -> 16,149
36,981 -> 36,561
929,52 -> 30,951
845,85 -> 318,612
114,731 -> 794,51
434,280 -> 406,308
530,513 -> 114,513
417,715 -> 417,273
44,845 -> 44,225
951,122 -> 450,623
32,707 -> 32,832
51,58 -> 51,806
165,305 -> 49,189
517,221 -> 942,221
125,233 -> 193,233
903,180 -> 101,982
123,303 -> 247,179
199,174 -> 546,521
185,860 -> 538,860
825,751 -> 825,784
454,720 -> 64,720
28,10 -> 974,956
626,760 -> 586,760
91,234 -> 10,234
973,939 -> 65,31
589,308 -> 255,308
547,945 -> 239,945
909,914 -> 111,116
484,182 -> 253,182
145,575 -> 339,575
215,143 -> 611,143
963,983 -> 20,40
220,733 -> 333,846
126,860 -> 940,46
715,823 -> 715,284
832,65 -> 436,65
923,496 -> 530,889
708,517 -> 708,764
154,681 -> 22,549
909,135 -> 57,987
225,966 -> 225,941
629,491 -> 629,17
927,349 -> 72,349
15,987 -> 983,19
265,912 -> 74,912
14,985 -> 988,11
986,64 -> 129,921
697,831 -> 943,831
379,143 -> 853,617
232,887 -> 623,887
947,473 -> 947,453
898,762 -> 218,762
599,386 -> 870,386
757,137 -> 757,496
437,285 -> 437,326
515,311 -> 515,63
305,703 -> 720,703
321,770 -> 88,537
75,48 -> 457,430
38,499 -> 38,544
481,896 -> 481,944
614,483 -> 437,483
647,430 -> 368,430
641,669 -> 641,691
849,626 -> 427,204
805,688 -> 805,536
102,315 -> 102,108
729,525 -> 770,525
234,702 -> 38,702
17,457 -> 526,457
369,155 -> 369,647
216,118 -> 216,43
342,384 -> 342,905
470,832 -> 314,676
179,318 -> 179,315
40,707 -> 547,707
771,236 -> 453,236
113,823 -> 826,110
731,642 -> 707,642
36,398 -> 810,398
233,447 -> 979,447
74,286 -> 907,286
939,223 -> 939,10
866,57 -> 866,656
978,20 -> 10,988
816,176 -> 50,942
293,868 -> 293,350
900,159 -> 148,911
58,84 -> 644,84
720,416 -> 720,906
935,31 -> 13,953
41,727 -> 221,727
633,112 -> 633,695
418,947 -> 418,574
632,711 -> 791,711
73,228 -> 73,861
59,447 -> 83,447
418,938 -> 418,638
922,352 -> 636,352
66,773 -> 66,868
69,678 -> 600,147
333,251 -> 298,251
371,803 -> 740,434
976,972 -> 976,165
896,415 -> 240,415
672,476 -> 860,476
202,291 -> 195,291
99,971 -> 518,552
284,858 -> 910,232
187,282 -> 187,627
157,445 -> 157,665
421,879 -> 38,496
155,431 -> 405,431
772,472 -> 315,929
69,818 -> 132,818
70,328 -> 70,800
471,788 -> 646,788
960,900 -> 97,37
258,566 -> 186,494
345,413 -> 306,413
897,173 -> 897,896
74,740 -> 74,795
679,238 -> 679,811
870,64 -> 64,870
30,869 -> 288,869
539,380 -> 539,862
452,692 -> 748,692
527,712 -> 527,139
725,504 -> 717,504
201,338 -> 636,338
626,719 -> 626,302
580,153 -> 274,459
654,215 -> 246,215
363,738 -> 363,192
335,502 -> 970,502
266,52 -> 266,442
125,127 -> 281,127

@ -0,0 +1,18 @@
#lang br
(require racket/file sugar rackunit)
(define fish (map string->number (string-split (file->string "06.rktd") ",")))
(define (simulate fish days)
(for/fold ([freqs (frequency-hash fish)]
#:result (apply + (hash-values freqs)))
([d (in-range days)])
(hash-set*
(for/hasheq ([(k v) (in-hash freqs)]
#:unless (zero? k))
(values (sub1 k) v))
6 (+ (hash-ref freqs 7 0) (hash-ref freqs 0 0))
8 (hash-ref freqs 0 0))))
(check-equal? (simulate fish 80) 361169)
(check-equal? (simulate fish 256) 1634946868992)

@ -0,0 +1 @@
1,1,3,5,3,1,1,4,1,1,5,2,4,3,1,1,3,1,1,5,5,1,3,2,5,4,1,1,5,1,4,2,1,4,2,1,4,4,1,5,1,4,4,1,1,5,1,5,1,5,1,1,1,5,1,2,5,1,1,3,2,2,2,1,4,1,1,2,4,1,3,1,2,1,3,5,2,3,5,1,1,4,3,3,5,1,5,3,1,2,3,4,1,1,5,4,1,3,4,4,1,2,4,4,1,1,3,5,3,1,2,2,5,1,4,1,3,3,3,3,1,1,2,1,5,3,4,5,1,5,2,5,3,2,1,4,2,1,1,1,4,1,2,1,2,2,4,5,5,5,4,1,4,1,4,2,3,2,3,1,1,2,3,1,1,1,5,2,2,5,3,1,4,1,2,1,1,5,3,1,4,5,1,4,2,1,1,5,1,5,4,1,5,5,2,3,1,3,5,1,1,1,1,3,1,1,4,1,5,2,1,1,3,5,1,1,4,2,1,2,5,2,5,1,1,1,2,3,5,5,1,4,3,2,2,3,2,1,1,4,1,3,5,2,3,1,1,5,1,3,5,1,1,5,5,3,1,3,3,1,2,3,1,5,1,3,2,1,3,1,1,2,3,5,3,5,5,4,3,1,5,1,1,2,3,2,2,1,1,2,1,4,1,2,3,3,3,1,3,5

@ -0,0 +1,13 @@
#lang br
(require racket/file sugar rackunit)
(define posns (map string->number (string-split (file->string "07.rktd") ",")))
(define/caching (gauss-summation x) (* (/ x 2) (+ x 1)))
(define (fuel-cost alignment [post-proc values])
(foldl (λ (posn res) (+ res (post-proc (abs (- alignment posn))))) 0 posns))
(define possible-alignments (remove-duplicates posns))
(check-equal? (apply min (map fuel-cost possible-alignments)) 349357)
(check-equal? (apply min (map (λ (pa) (fuel-cost pa gauss-summation)) possible-alignments)) 96708205)

@ -0,0 +1 @@
1101,1,29,67,1102,0,1,65,1008,65,35,66,1005,66,28,1,67,65,20,4,0,1001,65,1,65,1106,0,8,99,35,67,101,99,105,32,110,39,101,115,116,32,112,97,115,32,117,110,101,32,105,110,116,99,111,100,101,32,112,114,111,103,114,97,109,10,33,133,43,1060,890,12,15,136,42,25,96,694,522,893,204,204,1168,311,1046,1699,26,399,299,66,644,402,65,480,711,72,894,244,249,337,331,774,126,23,484,1299,662,404,235,86,1492,556,73,478,210,82,433,597,154,130,178,491,578,856,532,1191,544,256,831,252,1001,109,37,1290,317,376,22,742,496,930,118,28,376,73,247,942,895,38,675,138,387,203,271,104,65,1099,981,167,67,57,607,1095,202,225,1067,1757,324,127,785,266,518,135,914,1006,1402,578,28,548,211,673,302,525,208,115,92,514,518,71,1298,796,780,166,1341,475,273,101,1155,838,1219,901,727,497,168,543,416,174,31,755,865,106,358,236,186,369,550,465,617,375,535,1639,513,419,1377,1024,704,77,38,0,149,5,28,1163,149,1654,614,1201,89,1141,844,1390,1081,132,1385,52,1027,80,572,377,340,39,630,875,692,289,339,358,68,205,54,149,41,1208,1528,171,204,438,571,308,556,1372,426,204,18,31,51,40,287,1845,1721,441,240,875,901,328,800,341,59,530,134,275,11,7,7,1,1571,218,374,536,992,464,234,398,300,74,99,1163,1039,430,43,659,667,1115,407,257,717,657,249,46,109,734,67,1010,581,1070,738,478,621,183,224,1372,560,1573,1026,338,485,1138,1007,910,16,846,556,423,200,962,103,570,540,900,839,319,171,14,22,205,225,569,81,381,132,127,139,123,788,1571,35,830,65,677,1745,819,804,854,346,190,480,1500,76,1049,306,17,668,113,163,755,1015,718,1037,156,267,158,74,377,