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aoc-racket/typed/day04.rkt

23 lines
765 B
Racket

#lang typed/racket
(require typed/rackunit typed/openssl/md5)
(provide (all-defined-out))
(: q1 (-> String (U #f Natural)))
(define (q1 str)
(for/or : (U #f Natural) ([i : Natural (in-naturals)])
(define md5-key (string-append str (~a i)))
(define md5-hash (md5 (open-input-string md5-key)))
(and (string-prefix? md5-hash "00000") i)))
(: q2 (-> String (U #f Natural)))
(define (q2 str)
(for/or : (U #f Natural) ([i : Natural (in-naturals)])
(define md5-key (string-append str (~a i)))
(define md5-hash (md5 (open-input-string md5-key)))
(and (string-prefix? md5-hash "000000") i)))
(module+ test
(define input-str (file->string "../day04-input.txt"))
(check-equal? (q1 input-str) 346386)
(check-equal? (q2 input-str) 9958218))