Minor refactoring of Days 1 - 7.

src/02.rkt

@@ -13,17 +13,14 @@
 (define input (map parse (problem-input 2)))
 
 (define part1
-  (length (filter (λ (entry)
-                    (match-let* ([(list min max char pass) entry]
-                                 [occurrences (length (filter (∂ char=? char) pass))])
-                      (<= min occurrences max)))
-                  input)))
+  (count (match-lambda [(list min max char pass)
+                        (<= min (count (λ~> (char=? char)) pass) max)])
+         input))
 
 (define part2
-  (length (filter (λ (entry)
-                    (match-let* ([(list min max char pass) entry])
+  (count (match-lambda [(list min max char pass)
                         (xor (char=? (list-ref pass (sub1 min)) char)
-                           (char=? (list-ref pass (sub1 max)) char))))
-                  input)))
+                             (char=? (list-ref pass (sub1 max)) char))])
+         input))
 
 (show-solution part1 part2)

src/03.rkt

@@ -1,44 +1,16 @@
-#lang racket
+#lang curly-fn racket
 
 (require "../lib.rkt")
 
-(define test
-  (lists->vectors
-   (map string->list
-        '("..##......."
-          "#...#...#.."
-          ".#....#..#."
-          "..#.#...#.#"
-          ".#...##..#."
-          "..#.##....."
-          ".#.#.#....#"
-          ".#........#"
-          "#.##...#..."
-          "#...##....#"
-          ".#..#...#.#"))))
-
-(define input (lists->vectors (map string->list (problem-input 3))))
+(define input (problem-input 3))
 
 (define (trees grid right down)
-  (define width (vector-length (vector-ref grid 0)))
-  (for/sum ([i (range 0 (vector-length grid) down)])
-    (if (char=? #\#
-                (vector-ref (vector-ref grid i)
-                            (% (* (/ i down) right) width)))
-        1 0)))
-
-(define (test-input grid)
-  (define (print-test right down)
-    (let ([trees (trees grid right down)])
-      (printf "Part 2 test (~a right, ~a down): ~a\n"
-              right down trees)
-      trees))
-  (printf "Part 2 test: ~a\n"
-          (* (print-test 1 1)
-             (print-test 3 1)
-             (print-test 5 1)
-             (print-test 7 1)
-             (print-test 1 2))))
+  (define width (string-length (list-ref grid 0)))
+  (define height (length grid))
+  (count #{char=? #\#
+                  (string-ref (list-ref grid %)
+                              (modulo (* (/ % down) right) width))}
+         (range 0 height down)))
 
 (define part1
   (trees input 3 1))
@@ -50,5 +22,4 @@
      (trees input 7 1)
      (trees input 1 2)))
 
-(test-input test)
 (show-solution part1 part2)

src/04.rkt

@@ -4,21 +4,6 @@
 
 (define input (problem-input-grouped 4))
 
-(define test
-  "ecl:gry pid:860033327 eyr:2020 hcl:#fffffd
-byr:1937 iyr:2017 cid:147 hgt:183cm
-
-iyr:2013 ecl:amb cid:350 eyr:2023 pid:028048884
-hcl:#cfa07d byr:1929
-
-hcl:#ae17e1 iyr:2013
-eyr:2024
-ecl:brn pid:760753108 byr:1931
-hgt:179cm
-
-hcl:#cfa07d eyr:2025 pid:166559648
-iyr:2011 ecl:brn hgt:59in")
-
 (struct passport
   (byr iyr eyr hgt hcl ecl pid cid)
   #:transparent)
@@ -45,16 +30,12 @@ iyr:2011 ecl:brn hgt:59in")
     [(regexp #px"^(\\d{2})in$" (list _ hgt)) (<= 59 (string->number hgt) 76)]
     [_ #f]))
 
-(define (passports in)
-  (let* ([passport-entries (map (compose
-                                 (∂ map (compose
-                                         (∂ map ∂ (list string->symbol identity))
-                                         (∂r string-split ":")))
-                                 (∂r string-split " ")
-                                 (∂r string-replace "\n" " "))
-                                in)]
-         [passports (map (∂ foldl passport-set default-passport)
-                         passport-entries)]
+(define-values (part1 part2)
+  (let* ([passport-entries (map (λ~>> (string-split _ #px"[ \n]")
+                                      (map (match-lambda [(regexp #rx"(.+):(.+)" (list _ field value))
+                                                          (list (string->symbol field) value)])))
+                                input)]
+         [passports (map (∂ foldl passport-set default-passport) passport-entries)]
          [valid-raw? (struct/c passport string? string? string? string? string? string? string? any/c)]
          [valid? (struct/c passport
                            (and/c string? (∘ (integer-in 1920 2002) string->number))
@@ -68,7 +49,4 @@ iyr:2011 ecl:brn hgt:59in")
     (values (count valid-raw? passports)
             (count valid? passports))))
 
-(define-values (part1 part2)
-  (passports input))
-
 (show-solution part1 part2)

src/05.rkt

@@ -4,13 +4,16 @@
          "../lib.rkt")
 
 (define (string->seat str)
-  (string->number (string-append "#b" (regexp-replaces str '([#rx"F" "0"] [#rx"B" "1"] [#rx"L" "0"] [#rx"R" "1"])))))
+  (~>> str
+      (regexp-replaces _ '([#rx"F" "0"] [#rx"B" "1"] [#rx"L" "0"] [#rx"R" "1"]))
+      (string-append "#b")
+      string->number))
 
 (define input (map string->seat (problem-input 5)))
 
 (define-values (part1 part2)
-  (let* ([minimum ($ min input)]
-         [maximum ($ max input)]
+  (let* ([minimum (apply min input)]
+         [maximum (apply max input)]
          [seats (list->set (range minimum (add1 maximum)))]
          [filled (list->set input)])
     (values maximum (set-first (set-subtract seats filled)))))

src/07.rkt

@@ -22,10 +22,10 @@
 
 (define (count-bags graph source)
   (let ([neighbours (get-neighbours graph source)])
-    (apply + 1 (map (λ (neighbour)
+    (add1 (sum (map (λ (neighbour)
                       (let ([weight (edge-weight graph source neighbour)])
                         (* weight (count-bags graph neighbour))))
-                    neighbours))))
+                    neighbours)))))
 
 (define-values (part1 part2)
   (let*-values ([(contained contains) (strings->graphs input)]