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aoc-racket
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Matthew Butterick 4 years ago
parent bc77b0e75f
commit 3a72140709
1 changed files with 11 additions and 8 deletions
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19
2019/15.rkt
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@ -6,14 +6,17 @@
(apply append (map (curry make-list (add1 i)) '(0 1 0 -1)))))
(define (fft str [phase-count 1])
(for/fold ([ints (for/list ([c (in-string str)])
(string->number (string c)))]
#:result (take ints 8))
([pidx (in-range phase-count)])
(for/list ([patints (in-list (make-patintss ints))])
(modulo (abs (for/sum ([int (in-list (cons 0 ints))] ; cons 0 to burn off first patint
[patint (in-cycle patints)])
(* int patint))) 10))))
(define ints (for/list ([c (in-string str)])
(string->number (string c))))
(define patintss (make-patintss ints))
(time
(for/fold ([ints ints]
#:result (take ints 8))
([pidx (in-range phase-count)])
(for/list ([patints (in-list patintss)])
(modulo (abs (for/sum ([int (in-list (cons 0 ints))] ; cons 0 to burn off first patint
[patint (in-cycle patints)])
(* int patint))) 10)))))
(check-equal? (fft "80871224585914546619083218645595" 100) '(2 4 1 7 6 1 7 6))