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aoc-racket/2018/11.rkt

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#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 (★★)) _))