Merge branch 'main' of https://github.com/hunkyjimpjorps/AdventOfCode

1 files changed, 38 insertions, 0 deletions

diff --git a/aoc2023-racket/day-01/day-01.rkt b/aoc2023-racket/day-01/day-01.rkt
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+#lang racket
+
+(require advent-of-code
+         threading)
+
+(define calibration-values (fetch-aoc-input (find-session) 2023 1))
+
+(define (to-number str)
+  (match (string->number str)
+    [#false (hash-ref word-to-digit str)]
+    [n n]))
+
+(define (parse-calibration-value v valid)
+  (for/fold ([acc '()] [value v] #:result (+ (to-number (first acc)) (* 10 (to-number (last acc)))))
+            ([_ (in-naturals)])
+    #:break (equal? value "")
+    (let ([possible-prefix (findf (curry string-prefix? value) valid)])
+      (if possible-prefix
+          (values (cons possible-prefix acc) (substring value 1))
+          (values acc (substring value 1))))))
+
+(define (total-calibration input valid)
+  (~> input
+      (string-trim)
+      (string-split "\n")
+      (map (λ~> (parse-calibration-value valid)) _)
+      (apply + _)))
+
+;; part 1
+
+(define valid-for-part-1 (~> (range 1 10) (map ~a _)))
+(total-calibration calibration-values valid-for-part-1)
+
+;; part 2
+(define word-to-digit
+  (hash "one" 1 "two" 2 "three" 3 "four" 4 "five" 5 "six" 6 "seven" 7 "eight" 8 "nine" 9))
+(define valid-for-part-2 (append valid-for-part-1 (hash-keys word-to-digit)))
+(total-calibration calibration-values valid-for-part-2)