diff options
Diffstat (limited to '2021/day-03/day-03.rkt')
| -rw-r--r-- | 2021/day-03/day-03.rkt | 25 |
1 files changed, 7 insertions, 18 deletions
diff --git a/2021/day-03/day-03.rkt b/2021/day-03/day-03.rkt index f26d5a4..95b7efd 100644 --- a/2021/day-03/day-03.rkt +++ b/2021/day-03/day-03.rkt @@ -9,31 +9,20 @@ ;; part 1 (define most-common-bits - (for*/list ([row (in-list (apply map list data))] - [len (in-value (length data))]) - (if (> (count (λ (c) (char=? #\1 c)) row) (/ len 2)) - #\1 - #\0))) + (for*/list ([row (in-list (apply map list data))] [len (in-value (length data))]) + (if (> (count (λ (c) (char=? #\1 c)) row) (/ len 2)) #\1 #\0))) (define (bit-list->number lst) - (~> lst - (apply string _) - (string->number _ 2))) + (~> lst (apply string _) (string->number _ 2))) -(define gamma - (bit-list->number most-common-bits)) -(define epsilon - (~> most-common-bits - (map (λ (c) (if (char=? c #\1) #\0 #\1)) _) - bit-list->number)) +(define gamma (bit-list->number most-common-bits)) +(define epsilon (~> most-common-bits (map (λ (c) (if (char=? c #\1) #\0 #\1)) _) bit-list->number)) (* gamma epsilon) ;; part 2 (define (rating-search data comparison) - (for/fold ([candidates data] - #:result (bit-list->number (first candidates))) - ([bit (in-list most-common-bits)] - [bit-index (in-range 0 (length most-common-bits))]) + (for/fold ([candidates data] #:result (bit-list->number (first candidates))) + ([bit (in-list most-common-bits)] [bit-index (in-range 0 (length most-common-bits))]) #:break (= 1 (length candidates)) (define keep-bit (~> candidates |