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- #lang racket
- (require "../lib/utils.rkt")
- (define lines
- (call-with-input-file "input"
- (λ (fp)
- (get-lines fp))))
- (define (parse-data line)
- (map string->number (string-split line)))
- (define data (map parse-data lines))
- (define (diff lst)
- (let loop ((cur lst) (ret '()))
- (if (or (null? cur) (null? (cdr cur)))
- (reverse ret)
- (loop (cdr cur) (cons (- (cadr cur) (car cur)) ret)))))
- (define (predict lst)
- (if (andmap (λ (x) (= x (car lst))) lst)
- (car lst)
- (+ (last lst) (predict (diff lst)))))
- (apply + (map predict data))
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