From fcd6998f07bb9f44dafcb029156ae171ee4b0387 Mon Sep 17 00:00:00 2001 From: HJ Date: Thu, 14 Dec 2023 23:41:03 -0500 Subject: 2016 day 1 part 1 --- aoc2016/day-01/day-01.rkt | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) create mode 100644 aoc2016/day-01/day-01.rkt (limited to 'aoc2016') diff --git a/aoc2016/day-01/day-01.rkt b/aoc2016/day-01/day-01.rkt new file mode 100644 index 0000000..d18c819 --- /dev/null +++ b/aoc2016/day-01/day-01.rkt @@ -0,0 +1,38 @@ +#lang racket + +(require advent-of-code + threading) + +(struct posn (x y) #:transparent) +(struct dir (x y) #:transparent) + +(define/match (left _d) + [((dir 0 1)) (dir -1 0)] + [((dir -1 0)) (dir 0 -1)] + [((dir 0 -1)) (dir 1 0)] + [((dir 1 0)) (dir 0 1)]) + +(define/match (right _d) + [((dir 0 1)) (dir 1 0)] + [((dir 1 0)) (dir 0 -1)] + [((dir 0 -1)) (dir -1 0)] + [((dir -1 0)) (dir 0 1)]) + +(define/match (go _from _d _dist) + [((posn x y) (dir dx dy) dist) (posn (+ x (* dx dist)) (+ y (* dy dist)))]) + +(define input (~> (fetch-aoc-input (find-session) 2016 1 #:cache #true) string-trim (string-split ", "))) + +;; part 1 +(for/fold ([p (posn 0 0)] + [d (dir 0 1)] + #:result (+ (abs (posn-x p)) (abs (posn-y p)))) + ([instruction (in-list input)]) + (displayln (~a p " " d)) + (match instruction + [(regexp #rx"L(.*)" (list _ n)) (values (go p (left d) (string->number n)) + (left d))] + [(regexp #rx"R(.*)" (list _ n)) (values (go p (right d) (string->number n)) + (right d))])) + +;; part 2 -- cgit v1.2.3