28 lines
810 B
Scheme
28 lines
810 B
Scheme
(import (chicken string))
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(import (chicken format))
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(import (chicken io))
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(import (chicken sort))
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(import srfi-141)
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(define numbers (map string->number (string-split (read-line) ",")))
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; PART 1
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(let* ((sorted (sort numbers <))
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(median (list-ref sorted (floor/ (length numbers) 2)))
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(part1 (foldl (lambda (x y) (+ x (abs (- y median))))
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0 numbers)))
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(format #t "part 1: ~A~%" part1))
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; PART 2
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(define (triangular n) (/ (* n (+ n 1)) 2))
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(define (part2- avg)
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(foldl (lambda (x y) (+ x (triangular (abs (- y avg)))))
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0 numbers))
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(let* ((len (length numbers))
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(sum (foldl + 0 numbers))
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(avg-ceil (ceiling/ sum len))
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(avg-floor (floor/ sum len))
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(part2 (min (part2- avg-ceil) (part2- avg-floor))))
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(format #t "part 2: ~A~%" part2))
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