day 7 complete

1 files changed, 36 insertions, 0 deletions

diff --git a/2022/day-07/day-07.rkt b/2022/day-07/day-07.rkt
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+++ b/2022/day-07/day-07.rkt
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+#lang racket
+
+(require advent-of-code
+         fancy-app
+         threading
+         (only-in relation ->number))
+
+(define command-output (~> (fetch-aoc-input (find-session) 2022 7) (string-split "\n")))
+
+(define (parse-commands cmds)
+  (define (update-sizes h path size)
+    (match path
+      ['() h]
+      [(list* _ fs) (update-sizes (hash-update h path (+ _ size) 0) fs size)]))
+
+  (for/fold ([folders (hash)] [current-path '()] [previously-seen? #false] #:result folders)
+            ([cmd (in-list cmds)])
+    (match cmd
+      ["$ ls" (values folders current-path (hash-has-key? folders current-path))]
+      ["$ cd /" (values folders '("/") #false)]
+      ["$ cd .." (values folders (rest current-path) #false)]
+      [(regexp #px"\\$ cd (.+)" (list _ folder)) (values folders (cons folder current-path) #false)]
+      [(regexp #px"dir (.+)") (values folders current-path previously-seen?)]
+      [(regexp #px"(.+) (.+)" (list _ (app ->number size) _))
+       (cond
+         [previously-seen? (values folders current-path previously-seen?)]
+         [else (values (update-sizes folders current-path size) current-path previously-seen?)])])))
+
+(define folders (parse-commands command-output))
+
+;; part 1
+(for/sum ([(_ v) (in-hash folders)] #:when (<= v 100000)) v)
+
+;; part 2
+(define required-to-delete (- 30000000 (- 70000000 (hash-ref folders '("/")))))
+(~>> folders hash-values (filter (> _ required-to-delete)) (apply min))