From 46e2daa9af9a76591ad614d2d3db8d7030146e38 Mon Sep 17 00:00:00 2001
From: Jonathan Chan <jcxz@cs.ubc.ca>
Date: Sun, 6 Dec 2020 23:28:11 -0800
Subject: [PATCH] Refactored Day 7.

---
 src/07.rkt | 31 +++++++++++--------------------
 1 file changed, 11 insertions(+), 20 deletions(-)

diff --git a/src/07.rkt b/src/07.rkt
index ff26efe..2d59131 100644
--- a/src/07.rkt
+++ b/src/07.rkt
@@ -4,29 +4,20 @@
                     [get-neighbors get-neighbours])
          "../lib.rkt")
 
-(define (parse bag)
-  (match-let* ([(list _ outer inners) (regexp-match #rx"^(.+) bags contain (.+)$" bag)]
-               [inner-list (map (∘ (∂r string-trim " bag")
-                                   (∂r string-trim " bags"))
-                                (string-split (string-trim inners ".") ", "))]
-               [inner-bags (filter-map (match-lambda
-                                         [(regexp #px"(\\d+) (.+)" (list _ count style))
-                                          (cons (string->number count) style)]
-                                         [else #f])
-                                       inner-list)])
-    (cons outer inner-bags)))
+(define input (problem-input 7))
 
-(define input (map parse (problem-input 7)))
-
-(define (containment-graphs bags)
+(define (strings->graphs bags)
   (let ([contained (weighted-graph/directed '())]
         [contains (weighted-graph/directed '())])
     (for ([bag bags])
-      (match-let ([(list outer inners ...) bag])
-        (for ([inner inners])
-          (match-let ([(cons count style) inner])
-            (add-directed-edge! contained style outer count)
-            (add-directed-edge! contains outer style count)))))
+      (match-let ([(list _ outer inners) (regexp-match #rx"^(.+) bags contain (.+).$" bag)])
+        (for ([inner (string-split inners ",")])
+          (match inner
+            [(regexp #px"(\\d+) (.+) bags?" (list _ count inner))
+             (add-directed-edge! contained inner outer (string->number count))
+             (add-directed-edge! contains outer inner (string->number count))]
+            [else (add-vertex! contained outer)
+                  (add-vertex! contains outer)]))))
     (values contained contains)))
 
 (define (count-bags graph source multiplier)
@@ -38,7 +29,7 @@
        multiplier)))
 
 (define-values (part1 part2)
-  (let*-values ([(contained contains) (containment-graphs input)]
+  (let*-values ([(contained contains) (strings->graphs input)]
                 [(bfs-shiny-gold pred) (bfs contained "shiny gold")]
                 [(reachables) (count (∘ (∂ != +inf.0) cdr) (hash->list bfs-shiny-gold))]
                 [(total-bags) (count-bags contains "shiny gold" 1)])