diff options
Diffstat (limited to 'racket/aoc2020/day-03/day-03.rkt')
| -rw-r--r-- | racket/aoc2020/day-03/day-03.rkt | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/racket/aoc2020/day-03/day-03.rkt b/racket/aoc2020/day-03/day-03.rkt new file mode 100644 index 0000000..ee9edcf --- /dev/null +++ b/racket/aoc2020/day-03/day-03.rkt @@ -0,0 +1,16 @@ +#lang racket +(require "../../jj-aoc.rkt" + threading) + +(define (check-for-trees run rise) + (for*/sum ([(row i) (in-indexed (port->lines (open-day 3 2020)))] + #:when (= 0 (modulo i rise)) + [possible-tree (in-value (sequence-ref (in-cycle row) (* (/ run rise) i)))] + #:when (and (char=? possible-tree #\#))) + 1)) + +;; part 1 +(check-for-trees 3 1) + +;; part 2 +(~>> '((1 1) (3 1) (5 1) (7 1) (1 2)) (map (curry apply check-for-trees)) (apply *)) |