Overview
| Comment: | Day 1 solutions (both parts) |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA3-256: |
6b74a14c4253754be4e2923c00e54cb0 |
| User & Date: | joel on 2018-12-01 23:16:30 |
| Other Links: | manifest | tags |
Context
|
2018-12-02
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| 17:26 | Add Day 2 input and solutions check-in: 35dfec user: joel tags: trunk | |
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2018-12-01
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| 23:16 | Day 1 solutions (both parts) check-in: 6b74a1 user: joel tags: trunk | |
| 21:18 | Add Readme file check-in: 1c0a94 user: joel tags: trunk | |
Changes
Added day01.rkt version [433e28].
> > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 |
#lang racket
(require rackunit)
(define input (file->lines "day01-input.txt"))
(define start-frequency 0)
(define (day01-part1)
(apply + start-frequency (map string->number input)))
(module+ test
(check-equal? (day01-part1) 486)) ; Correct answer for part1
(define (day01-part2 [freq-changes (map string->number input)]
[start-from start-frequency]
[seen-frequencies (list start-frequency)])
(define run-through
(for/fold ([seen seen-frequencies]
[current-freq start-from]
#:result seen)
([freq-change (in-list freq-changes)])
#:final (member (+ current-freq freq-change) seen)
(values (append seen (list (+ current-freq freq-change))) (+ current-freq freq-change))))
(cond
[(check-duplicates run-through)
(last run-through)]
[else
(day01-part2 freq-changes (last run-through) run-through)]))
(module+ test
(check-equal? (day01-part2 '(3 3 4 -2 -4)) 10)
(check-equal? (day01-part2 '(-6 3 8 5 -6)) 5)
(check-equal? (day01-part2 '(7 7 -2 -7 -4)) 14)
; Actually getting the correct answer for my input takes a really long time
; (check-equal? (day01-part2) 69285)
)
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