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-rw-r--r--2020/day-04/day-04.rkt49
-rw-r--r--2020/day-05/day-05.rkt44
2 files changed, 93 insertions, 0 deletions
diff --git a/2020/day-04/day-04.rkt b/2020/day-04/day-04.rkt
new file mode 100644
index 0000000..3c7db89
--- /dev/null
+++ b/2020/day-04/day-04.rkt
@@ -0,0 +1,49 @@
+#lang racket
+(require "../../jj-aoc.rkt"
+ threading)
+
+(define passports
+ (~> (open-day 4 2020)
+ (port->string)
+ (string-split "\n\n")
+ (map (λ~> (string-replace "\n" " ")) _)))
+
+;; part 1
+(define required-fields
+ (list "byr:"
+ "iyr:"
+ "eyr:"
+ "hgt:"
+ "hcl:"
+ "ecl:"
+ "pid:"))
+
+(define (valid-passport? p)
+ (andmap (λ (s) (string-contains? p s)) required-fields))
+
+(count valid-passport? passports)
+
+;; part 2
+(define passport-fields
+ (for/list ([p (in-list passports)]
+ #:when (valid-passport? p))
+ (~> p
+ string-split
+ (map (curryr string-split ":") _)
+ flatten
+ (apply hash _))))
+
+(define (valid-byr p)
+ (define year (string->number (hash-ref p "byr")))
+ (and (<= year 1920)
+ (>= year 2002)))
+
+(define (valid-iyr p)
+ (define year (string->number (hash-ref p "iyr")))
+ (and (<= year 2010)
+ (>= year 2020)))
+
+(define (valid-eyr p)
+ (define year (string->number (hash-ref p "iyr")))
+ (and (<= year 2020)
+ (>= year 2030))) \ No newline at end of file
diff --git a/2020/day-05/day-05.rkt b/2020/day-05/day-05.rkt
new file mode 100644
index 0000000..93c54a2
--- /dev/null
+++ b/2020/day-05/day-05.rkt
@@ -0,0 +1,44 @@
+#lang racket
+(require "../../jj-aoc.rkt"
+ threading
+ algorithms)
+
+(define tickets
+ (for/list
+ ([l (in-lines (open-day 5 2020))])
+ (~>> l
+ (regexp-match #px"(.{7})(.{3})" )
+ rest)))
+
+(define (find-place str min-p max-p l r)
+ (if (string=? "" str)
+ min-p
+ (let ([p-range (/ (add1 (- max-p min-p)) 2)]
+ [c (substring str 0 1)])
+ (cond
+ [(string=? c l)
+ (find-place (substring str 1) min-p (- max-p p-range) l r)]
+ [(string=? c r)
+ (find-place (substring str 1) (+ min-p p-range) max-p l r)]))))
+
+(define (find-row str) (find-place str 0 127 "F" "B"))
+(define (find-col str) (find-place str 0 7 "L" "R"))
+
+(define (ticket-id t)
+ (let ([row (find-row (first t))]
+ [col (find-col (second t))])
+ (+ col (* 8 row))))
+
+;; part 1
+(define occupied-seats
+ (~>> (for/list ([t (in-list tickets)]) (ticket-id t))))
+
+(apply max occupied-seats)
+
+;; part 2
+(set-first
+ (set-subtract (list->set (inclusive-range (apply min occupied-seats)
+ (apply max occupied-seats)))
+ (list->set occupied-seats)))
+
+