Initial commit

2019/day06/day06.rkt

@@ -0,0 +1,23 @@
+#lang racket
+
+(require racket/string
+         graph)
+
+(define (read-graph filename)
+  (with-input-from-file filename
+    (lambda ()
+     (define g (unweighted-graph/directed '()))
+     (for ([line (in-lines)])
+       (define bodies (string-split line ")"))
+       (add-edge! g (car bodies) (cadr bodies)))
+     g)))
+
+(define (part1 filename)
+  (define g (read-graph filename))
+  (define-values (dists _) (bfs g "COM"))
+  (for/sum ([i (in-hash-values dists)]) i))
+
+(define (part2 filename)
+  (define g (read-graph filename))
+  (define-values (dists _) (bfs g "YOU"))
+  (- (hash-ref dists "SAN") 2))

2019/day06/test

@@ -0,0 +1,11 @@
+COM)B
+B)C
+C)D
+D)E
+E)F
+B)G
+G)H
+D)I
+E)J
+J)K
+K)L

2019/day06/test2

@@ -0,0 +1,13 @@
+COM)B
+B)C
+C)D
+D)E
+E)F
+B)G
+G)H
+D)I
+E)J
+J)K
+K)L
+K)YOU
+I)SAN