#lang br (require racket/file rackunit) (define depths (map string->number (file->lines "01.rktd"))) (define (positive-deltas depths) (filter positive? (for/list ([d1 (in-list depths)] [d2 (in-list (cdr depths))]) (- d2 d1)))) (check-equal? (length (positive-deltas depths)) 1167) (define (trios depths) (for/list ([d1 (in-list depths)] [d2 (in-list (cdr depths))] [d3 (in-list (cddr depths))]) (+ d1 d2 d3))) (check-equal? (length (positive-deltas (trios depths))) 1130)