From 5926b5cd3f563f6fc92e7e264aafe00e61a5f2e0 Mon Sep 17 00:00:00 2001
From: Peter Tillemans <pti@snamellit.com>
Date: Thu, 19 Dec 2024 14:26:56 +0100
Subject: [PATCH] clean up day 19

---
 src/2024/day19.lisp | 87 ++++++++-------------------------------------
 1 file changed, 14 insertions(+), 73 deletions(-)

diff --git a/src/2024/day19.lisp b/src/2024/day19.lisp
index d4930cd..fe30e34 100644
--- a/src/2024/day19.lisp
+++ b/src/2024/day19.lisp
@@ -43,72 +43,13 @@ bbrgwb"))
 (defparameter sample-data 
   (parse-input sample-text))
 
-(defstruct node
-  name
-  terminates
-  next)
-
-(defun towel-tree (towels word)
-  (let ((towel-tree (make-hash-table))
-	(terminates nil))
-    (loop
-      for towel in towels
-      if (emptyp towel)
-	do (setf terminates t)
-      else
-	do (setf (gethash (char towel 0) towel-tree)
-		 (sort
-		  (let ((r (subseq towel 1)))
-		    (cons r (gethash (char towel 0) towel-tree)))
-		  #'(lambda (a b)
-		      (cond
-			((< (length a) (length b)) t)
-			((> (length a) (length b)) nil)
-			(t (string-lessp a b)))
-		      )))
-	   (loop
-	     for k being the hash-keys in towel-tree
-	     for v being the hash-values in towel-tree
-	     do (setf (gethash k towel-tree) (towel-tree v (concatenate 'string word (list k))))      
-	     )
-	   (make-node
-	    :name word
-	    :terminates terminates
-	    :next towel-tree))))
-
-(defun show-tree (tree &optional (depth 0))
-  (loop
-    for k being the hash-keys in (node-next tree)
-    for v being the hash-values in (node-next tree)
-    do (format t "~v@{~A~:*~}" depth "  ")
-       (format t "~A(~A)~%" k (if (node-terminates v) " OK" ""))
-       (show-tree  v (1+ depth))))
-
-(defun valid-pattern-p-old (og-tree pattern)
-  (defun check (tree pattern word words)
-    (let ((terminate (node-terminates tree)))
-      (if (emptyp pattern)
-	  terminate
-	  (let* ((c (char pattern 0))
-		 (np (subseq pattern 1))
-		 (nw (concatenate 'string word (list c))))
-	    (or
-	     (if-let ((nt (gethash c (node-next tree))))
-	       (check nt np nw words))
-	     (and terminate
-		  (if-let ((nt (gethash c (node-next og-tree))))
-		    (check nt np "" (cons word words))
-		    ))
-	     )))))
-  (check og-tree pattern "" '()))
-
-(defvar *patterns* (make-hash-table :test #'equal))
-(defvar *valid-patterns* (make-hash-table :test #'equal))
-(defvar *possible-patterns* (make-hash-table :test #'equal))
+(defvar *pattern-cache* (make-hash-table :test #'equal))
+(defvar *valid-cache* (make-hash-table :test #'equal))
+(defvar *possible-cache* (make-hash-table :test #'equal))
 (defun reset-patterns ()
-  (setf *patterns* (make-hash-table :test #'equal))
-  (setf *valid-patterns* (make-hash-table :test #'equal))
-  (setf *possible-patterns* (make-hash-table :test #'equal))
+  (setf *pattern-cache* (make-hash-table :test #'equal))
+  (setf *valid-cache* (make-hash-table :test #'equal))
+  (setf *possible-cache* (make-hash-table :test #'equal))
   )
 
 (defun string-prefix-p (prefix string)
@@ -118,20 +59,20 @@ bbrgwb"))
 
 (defun remaining-patterns (towels pattern)
   (or
-   (gethash pattern *patterns*)
+   (gethash pattern *pattern-cache*)
    (let ((remaining (loop
 		      for towel in towels
 		      if (string-prefix-p towel pattern)
 			collect (subseq pattern (length towel))
 		      )))
-     (setf (gethash pattern *patterns*) remaining))))
+     (setf (gethash pattern *pattern-cache*) remaining))))
 
 (defun valid-pattern-p (towels pattern)
   (multiple-value-bind (is-valid found)
-      (gethash pattern *valid-patterns*)
+      (gethash pattern *valid-cache*)
     (if found
 	is-valid
-	(setf (gethash pattern *valid-patterns*)
+	(setf (gethash pattern *valid-cache*)
 	      (if (emptyp pattern)
 		  t
 		  (if-let (ps (remaining-patterns towels pattern))
@@ -145,7 +86,7 @@ bbrgwb"))
 (defun towels-to-regex (onsen)
   (format nil "^(~{~A~^|~})*$" (onsen-towels onsen)))
 
-(defun valid-patterns (onsen)
+(defun valid-cache (onsen)
   (reset-patterns)
   (loop
     for pattern in (onsen-patterns onsen)
@@ -154,10 +95,10 @@ bbrgwb"))
 
 (defun possible-patterns (towels pattern)
   (multiple-value-bind (n found)
-      (gethash pattern *possible-patterns*)
+      (gethash pattern *possible-cache*)
     (if found
 	n
-	(setf (gethash pattern *possible-patterns*)
+	(setf (gethash pattern *possible-cache*)
 	      (if (emptyp pattern)
 		  1		  
 		  (if-let (ps (remaining-patterns towels pattern))
@@ -170,7 +111,7 @@ bbrgwb"))
     ))
 
 (defun part1 (onsen)
-  (format nil "~A" (length (valid-patterns onsen))))
+  (format nil "~A" (length (valid-cache onsen))))
 
 (defun part2 (data)
   (reset-patterns)