d10 p1

5 years ago · 3d0609e96a
parent 285da9a99a
commit 3d0609e96a
2 changed files with 96 additions and 0 deletions
--- a/2019/10.rkt
+++ b/2019/10.rkt
@ -0,0 +1,76 @@
+#lang br
+(require racket/file rackunit)
+
+(define (string->asteroids str)
+  (for*/list ([(row ridx) (in-indexed (string-split str))]
+              [(col cidx) (in-indexed row)]
+              #:when (char=? #\# col))
+    (+ cidx (* +i ridx))))
+
+(define ((count-visible roids) roid-origin)
+  (length (remove-duplicates (for/list ([roid (in-list roids)]
+                                        #:unless (= roid-origin roid))
+                               (angle (- roid roid-origin))))))
+
+(define (find-best roids)
+  (argmax (count-visible roids) roids))
+
+(check-equal? (find-best (string->asteroids "......#.#.
+#..#.#....
+..#######.
+.#.#.###..
+.#..#.....
+..#....#.#
+#..#....#.
+.##.#..###
+##...#..#.
+.#....####")) 5+8i)
+
+(check-equal? (find-best (string->asteroids "#.#...#.#.
+.###....#.
+.#....#...
+##.#.#.#.#
+....#.#.#.
+.##..###.#
+..#...##..
+..##....##
+......#...
+.####.###.")) 1+2i)
+
+(check-equal? (find-best (string->asteroids ".#..#..###
+####.###.#
+....###.#.
+..###.##.#
+##.##.#.#.
+....###..#
+..#.#..#.#
+#..#.#.###
+.##...##.#
+.....#.#..")) 6+3i)
+
+(check-equal? (find-best (string->asteroids ".#..##.###...#######
+##.############..##.
+.#.######.########.#
+.###.#######.####.#.
+#####.##.#.##.###.##
+..#####..#.#########
+####################
+#.####....###.#.#.##
+##.#################
+#####.##.###..####..
+..######..##.#######
+####.##.####...##..#
+.#####..#.######.###
+##...#.##########...
+#.##########.#######
+.####.#.###.###.#.##
+....##.##.###..#####
+.#.#.###########.###
+#.#.#.#####.####.###
+###.##.####.##.#..##")) 11+13i)
+
+;; 1
+(define roids (string->asteroids (file->string "10.rktd")))
+(check-eq?
+ ((count-visible roids) (find-best roids))
+ 214)
--- a/2019/10.rktd
+++ b/2019/10.rktd
@ -0,0 +1,20 @@
+.###.###.###.#####.#
+#####.##.###..###..#
+.#...####.###.######
+######.###.####.####
+#####..###..########
+#.##.###########.#.#
+##.###.######..#.#.#
+.#.##.###.#.####.###
+##..#.#.##.#########
+###.#######.###..##.
+###.###.##.##..####.
+.##.####.##########.
+#######.##.###.#####
+#####.##..####.#####
+##.#.#####.##.#.#..#
+###########.#######.
+#.##..#####.#####..#
+#####..#####.###.###
+####.#.############.
+####.#.#.##########.