From cdf29bac8a451008c587fc8a46099144047be15a Mon Sep 17 00:00:00 2001
From: Oscar Najera <hi@oscarnajera.com>
Date: Mon, 5 Dec 2022 13:03:12 +0100
Subject: [AoC2022] Elisp 05

---
 AoC2022/05/solver.el | 45 ++++++++++++++++++++++++++++++---------------
 1 file changed, 30 insertions(+), 15 deletions(-)

(limited to 'AoC2022/05/solver.el')

diff --git a/AoC2022/05/solver.el b/AoC2022/05/solver.el
index 59faf65..edcd7cc 100644
--- a/AoC2022/05/solver.el
+++ b/AoC2022/05/solver.el
@@ -15,36 +15,51 @@
 ;;
 ;;; Code:
 (require 'subr-x)
+
 (defun solver-build-stacks ()
   (let* ((stacks-len (length
                       (split-string
                        (buffer-substring-no-properties (line-beginning-position) (line-end-position)))))
          (stacks (make-vector stacks-len nil))
          next)
-    (message "%S" (list stacks-len (split-string
-                       (buffer-substring-no-properties (point) (line-end-position)))))
-
     (while (setq next (search-backward "]" nil t))
       (push (intern (string (char-before)))
             (aref stacks (/ (- next (line-beginning-position) 1) 4))))
     stacks))
 
-(defun solver-apply-moves (stacks)
+(defun solver-single-move! (stacks amount from to)
+  (dotimes (_ amount)
+    (push (pop (aref stacks from)) (aref stacks to))))
+
+(defun solver-bulk-move! (stacks amount from to)
+  (setf (aref stacks to)
+        (append (seq-take (aref stacks from) amount)
+                (aref stacks to)))
+  (setf (aref stacks from) (seq-drop (aref stacks from) amount)))
+
+(defun solver-apply-moves (execution stacks)
   (while (re-search-forward (rx bol "move " (group (+ digit)) " from " (group (+ digit)) " to " (group (+ digit))) nil t)
-    (let ((from (1- (string-to-number (match-string 2))))
+    (let ((amount (string-to-number (match-string 1)))
+          (from (1- (string-to-number (match-string 2))))
           (to (1- (string-to-number (match-string 3)))))
-      (dotimes (_ (string-to-number (match-string 1)))
-        (push (pop (aref stacks from)) (aref stacks to)))))
+      (funcall execution stacks amount from to)))
   stacks)
 
-'(T P G V Q P F D H)
-(with-temp-buffer
-  (insert-file-contents "input")
-  (re-search-forward "^ 1")
-  (thread-last
-    (solver-build-stacks)
-    (solver-apply-moves)
-    (seq-map #'car)))
+(defun solver (execution)
+  (with-temp-buffer
+    (insert-file-contents "input")
+    (re-search-forward "^ 1")
+    (thread-last
+      (solver-build-stacks)
+      (solver-apply-moves execution)
+      (seq-map #'car))))
+
+(ert-deftest solver-solutions ()
+  (should (equal '(T P G V Q P F D H)
+                 (solver #'solver-single-move!)))
+  (should (equal '(D M R D F R H H H)
+                 (solver #'solver-bulk-move!))))
+
 
 (provide 'solver)
 ;;; solver.el ends here
-- 
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