From 0adb2045177f99c8d9645f96ac724eb94d709217 Mon Sep 17 00:00:00 2001 From: Matthew Butterick Date: Mon, 10 Dec 2018 23:01:35 -0800 Subject: [PATCH] d11 p1 --- 2018/11.rkt | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) create mode 100644 2018/11.rkt diff --git a/2018/11.rkt b/2018/11.rkt new file mode 100644 index 0000000..4b81e00 --- /dev/null +++ b/2018/11.rkt @@ -0,0 +1,35 @@ +#lang debug br +(require sugar/cache) + +(define (hundreds-digit x) + (quotient (modulo x 1000) 100)) + +(define current-serial (make-parameter 0)) + +(define/caching (power-at x y) + (define rack-id (+ x 10)) + (- (hundreds-digit (* (+ (* rack-id y) (current-serial)) rack-id)) 5)) + +(define (grid-scores size-min [size-max size-min]) + (for*/list ([side (in-range size-min (add1 size-max))] + [x (in-range 1 (- 301 side))] + [y (in-range 1 (- 301 side))]) + (list x y + (for*/sum ([x (in-range x (+ side x))] + [y (in-range y (+ side y))]) + (power-at x y))))) + +(define (★) + (parameterize ([current-serial 7803]) + (take (argmax third (grid-scores 3)) 2))) + +#;(grid-scores 1 300) + +#;(define (★★) + ) +#;(★★) + +(module+ test + (require rackunit) + #;(check-equal? (time (★)) '(20 51)) + #;(check-equal? (time (★★)) _)) \ No newline at end of file