diff options
Diffstat (limited to '2021/day-11/day-11.rkt')
| -rw-r--r-- | 2021/day-11/day-11.rkt | 59 |
1 files changed, 18 insertions, 41 deletions
diff --git a/2021/day-11/day-11.rkt b/2021/day-11/day-11.rkt index cb784f0..bc22991 100644 --- a/2021/day-11/day-11.rkt +++ b/2021/day-11/day-11.rkt @@ -9,11 +9,8 @@ (apply append))) (define octopus-data - (~>> (for/list ([l (in-lines (open-day 11 2021))] - #:unless (equal? l "")) - (~>> l - string->list - (map (λ~>> ~a string->number)))) + (~>> (for/list ([l (in-lines (open-day 11 2021))] #:unless (equal? l "")) + (~>> l string->list (map (λ~>> ~a string->number)))) (apply append) (map cons coords) make-hash)) @@ -23,24 +20,18 @@ (define (adjacent-to coord) (match-define (cons r c) coord) - (for*/list ([row (in-list '(-1 0 1))] - [col (in-list '(-1 0 1))] - #:unless (= 0 row col)) + (for*/list ([row (in-list '(-1 0 1))] [col (in-list '(-1 0 1))] #:unless (= 0 row col)) (cons (+ r row) (+ c col)))) (define (simulate-octopi-step data) (define flashed-this-step (mutable-set)) - - (let look-for-more-flashes - ([octopi (for/hash ([(k v) data]) - (values k (add1 v)))] - [flashes-so-far 0]) - (define-values (next-octopus-update - flashes-this-update) + + (let look-for-more-flashes ([octopi (for/hash ([(k v) data]) + (values k (add1 v)))] + [flashes-so-far 0]) + (define-values (next-octopus-update flashes-this-update) (for*/fold ([octopi octopi] [flashes 0]) - ([(p x) (in-hash octopi)] - #:when (> x 9) - #:unless (set-member? flashed-this-step p)) + ([(p x) (in-hash octopi)] #:when (> x 9) #:unless (set-member? flashed-this-step p)) (set-add! flashed-this-step p) (define flashed-octopi (for*/fold ([o (hash-set octopi p 0)]) @@ -48,32 +39,18 @@ #:when (hash-has-key? o adj) #:unless (set-member? flashed-this-step adj)) (hash-update o adj add1))) - (values flashed-octopi - (add1 flashes)))) + (values flashed-octopi (add1 flashes)))) (if (> flashes-this-update 0) - (look-for-more-flashes next-octopus-update - (+ flashes-so-far - flashes-this-update)) - (values next-octopus-update - flashes-so-far)))) + (look-for-more-flashes next-octopus-update (+ flashes-so-far flashes-this-update)) + (values next-octopus-update flashes-so-far)))) ;; part 1 -(for/fold ([octopi octopus-data] - [total-flashes 0] #:result total-flashes) - ([step (in-range 100)]) - (define-values [next-state - flashes-from-this-state] - (simulate-octopi-step octopi)) - (values next-state - (+ total-flashes flashes-from-this-state))) +(for/fold ([octopi octopus-data] [total-flashes 0] #:result total-flashes) ([step (in-range 100)]) + (define-values [next-state flashes-from-this-state] (simulate-octopi-step octopi)) + (values next-state (+ total-flashes flashes-from-this-state))) ;; part 2 -(for/fold ([octopi octopus-data] - [synchro-step 0] #:result synchro-step) - ([step (in-naturals 1)]) - (define-values [next-state - flashes-from-this-state] - (simulate-octopi-step octopi)) +(for/fold ([octopi octopus-data] [synchro-step 0] #:result synchro-step) ([step (in-naturals 1)]) + (define-values [next-state flashes-from-this-state] (simulate-octopi-step octopi)) #:final (= flashes-from-this-state 100) - (values next-state - step)) + (values next-state step)) |