| blob | f1e79c830bbb12603b23ba2e61397a467c0fe039 |
1 (require (only (lib "1.ss" "srfi") filter))\r
2 \r
3 (define *grid* '((08 02 22 97 38 15 00 40 00 75 04 05 07 78 52 12 50 77 91 08)\r
4 (49 49 99 40 17 81 18 57 60 87 17 40 98 43 69 48 04 56 62 00)\r
5 (81 49 31 73 55 79 14 29 93 71 40 67 53 88 30 03 49 13 36 65)\r
6 (52 70 95 23 04 60 11 42 69 24 68 56 01 32 56 71 37 02 36 91)\r
7 (22 31 16 71 51 67 63 89 41 92 36 54 22 40 40 28 66 33 13 80)\r
8 (24 47 32 60 99 03 45 02 44 75 33 53 78 36 84 20 35 17 12 50)\r
9 (32 98 81 28 64 23 67 10 26 38 40 67 59 54 70 66 18 38 64 70)\r
10 (67 26 20 68 02 62 12 20 95 63 94 39 63 08 40 91 66 49 94 21)\r
11 (24 55 58 05 66 73 99 26 97 17 78 78 96 83 14 88 34 89 63 72)\r
12 (21 36 23 09 75 00 76 44 20 45 35 14 00 61 33 97 34 31 33 95)\r
13 (78 17 53 28 22 75 31 67 15 94 03 80 04 62 16 14 09 53 56 92)\r
14 (16 39 05 42 96 35 31 47 55 58 88 24 00 17 54 24 36 29 85 57)\r
15 (86 56 00 48 35 71 89 07 05 44 44 37 44 60 21 58 51 54 17 58)\r
16 (19 80 81 68 05 94 47 69 28 73 92 13 86 52 17 77 04 89 55 40)\r
17 (04 52 08 83 97 35 99 16 07 97 57 32 16 26 26 79 33 27 98 66)\r
18 (88 36 68 87 57 62 20 72 03 46 33 67 46 55 12 32 63 93 53 69)\r
19 (04 42 16 73 38 25 39 11 24 94 72 18 08 46 29 32 40 62 76 36)\r
20 (20 69 36 41 72 30 23 88 34 62 99 69 82 67 59 85 74 04 36 16)\r
21 (20 73 35 29 78 31 90 01 74 31 49 71 48 86 81 16 23 57 05 54)\r
22 (01 70 54 71 83 51 54 69 16 92 33 48 61 43 52 01 89 19 67 48)))\r
23 \r
24 (define *length* 4)\r
25 \r
26 (define (start-points)\r
27 (let ((height (length *grid*))\r
28 (width (length (car *grid*))))\r
29 (cross (numbers 0 (- width *length*))\r
30 (numbers 0 (- height *length*)))))\r
31 \r
32 (define (splice x y dx dy)\r
33 (let loop ((x* x)\r
34 (y* y)\r
35 (l* *length*))\r
36 (if (zero? l*)\r
37 '()\r
38 (cons (get x* y*) (loop (+ x* dx)\r
39 (+ y* dy)\r
40 (sub1 l*))))))\r
41 \r
42 (define (solve)\r
43 (apply max \r
44 (map (lambda (p)\r
45 (apply max\r
46 (map (lambda (dx dy)\r
47 (display p) (newline)\r
48 (apply * (splice (car p) (cdr p) dx dy)))\r
49 '(+1 0 +1 +1)\r
50 '( 0 +1 +1 -1))))\r
51 (start-points))))\r
52 \r
53 ;;;;\r
54 \r
55 (define (within-bounds? x y)\r
56 (and (>= x 0)\r
57 (< x (length (car *grid*)))\r
58 (>= y 0)\r
59 (< y (length *grid*))))\r
60 \r
61 (define (get x y)\r
62 (if (within-bounds? x y)\r
63 (list-ref (list-ref *grid* y) x)\r
64 -1))\r
65 \r
66 (define (numbers a b)\r
67 (cond ((> a b) null)\r
68 (else (cons a (numbers (add1 a) b)))))\r
69 \r
70 (define (cross l1 l2)\r
71 (if (null? l1)\r
72 '()\r
73 (append (map (lambda (x) (cons (car l1) x)) l2)\r
74 (cross (cdr l1) l2))))\r
75 \r
76 (solve)\r
77 \r
78 ;; Incorrect - 96059601\r
79 ;; - 51267216