From 8ab65dc2da1742eb86ec636c50c7018385b68167 Mon Sep 17 00:00:00 2001 From: "J.J" Date: Thu, 30 Nov 2023 17:10:00 -0500 Subject: prep for 2023, renaming for consistency --- 2020/day-13/day-13.rkt | 32 -------------------------------- 1 file changed, 32 deletions(-) delete mode 100644 2020/day-13/day-13.rkt (limited to '2020/day-13') diff --git a/2020/day-13/day-13.rkt b/2020/day-13/day-13.rkt deleted file mode 100644 index b53f045..0000000 --- a/2020/day-13/day-13.rkt +++ /dev/null @@ -1,32 +0,0 @@ -#lang racket - -(require advent-of-code - (only-in relation ->number) - threading) - -(define (process-ids str) - (~> str (string-split ",") (filter-map (λ (s) (string->number s 10 'number-or-false)) _))) - -(match-define (regexp #px"(\\d+)\n(.+)" (list _ (app ->number timestamp) raw-bus-ids)) - (fetch-aoc-input (find-session) 2020 13)) - -(define bus-ids (process-ids raw-bus-ids)) - -;; part 1 -(for/first ([minute (in-naturals timestamp)] - #:do [(define departing-bus - (for/first ([b bus-ids] #:when (= 0 (remainder minute b))) - b))] - #:when departing-bus) - (* departing-bus (- minute timestamp))) - -;; part 2 -(for/fold ([step 1] [current-timestamp 1] #:result current-timestamp) - ([b* (in-list (string-split (string-trim raw-bus-ids) ","))] - [offset (in-naturals)] - #:unless (equal? b* "x") - #:do [(define bus (->number b*))]) - (values - (* step bus) - (for/first ([n (in-range current-timestamp +inf.0 step)] #:when (= 0 (remainder (+ n offset) bus))) - n))) -- cgit v1.2.3