1 files changed, 49 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