35 lines
848 B
Scheme
35 lines
848 B
Scheme
(import (chicken io)
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(chicken sort)
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srfi-1
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srfi-152)
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(define (read-input #!optional (port (current-input-port)))
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(map string->number (string-split (read-line port) ",")))
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(define (median lst)
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(list-ref (sort lst <=) (/ (length lst) 2)))
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(define (part1 in)
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(let ((target-pos (median in)))
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(apply + (map (lambda (x) (abs (- x target-pos))) in))))
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(define (cost start end)
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(let ((dist (abs (- start end))))
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(/ (* dist (+ dist 1)) 2)))
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(define (total-fuel target-pos in)
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(apply + (map (lambda (x) (cost target-pos x)) in)))
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(define (part2 in)
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(apply min
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(let ((min-in (apply min in))
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(max-in (apply max in)))
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(let lp ((pos min-in)
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(fuels '()))
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(if (> pos max-in)
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fuels
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(lp (+ 1 pos) (cons (total-fuel pos in) fuels)))))))
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(let ((in (read-input)))
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(print (part1 in))
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(print (part2 in)))
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