From c3cf19fc1ff67d89d69eb80e974bc330daebb202 Mon Sep 17 00:00:00 2001
From: Oscar Najera <hi@oscarnajera.com>
Date: Thu, 8 Dec 2022 14:16:07 +0100
Subject: [AoC2022] Elisp 07

---
 AoC2022/07/solver.el | 58 ++++++++++++++++++++++++----------------------------
 1 file changed, 27 insertions(+), 31 deletions(-)

(limited to 'AoC2022/07/solver.el')

diff --git a/AoC2022/07/solver.el b/AoC2022/07/solver.el
index 38354ff..910a81d 100644
--- a/AoC2022/07/solver.el
+++ b/AoC2022/07/solver.el
@@ -17,35 +17,23 @@
 
 
 (require 'cl-lib)
+(require 'subr-x)
 
-  (insert "$ cd /
-$ ls
-dir a
-14848514 b.txt
-8504156 c.dat
-dir d
-$ cd a
-$ ls
-dir e
-29116 f
-2557 g
-62596 h.lst
-$ cd e
-$ ls
-584 i
-$ cd ..
-$ cd ..
-$ cd d
-$ ls
-4060174 j
-8033020 d.log
-5626152 d.ext
-7214296 k")
+(ert-deftest test-solver ()
+  (with-temp-buffer
+    (insert-file-contents "input")
+    (let* ((dir-sizes
+            (thread-first
+              (split-string (buffer-string) "\n")
+              (solver-parse-listing)
+              (solver-aggregate-size)))
+           (total-disk 70000000)
+           (free-disk (- total-disk (cadr dir-sizes)))
+           (needed 30000000)
+           (to-free (- needed free-disk)))
+      (should (= 1845346 (solver-add-dir-size dir-sizes)))
+      (should (= 3636703 (solver-delete-what dir-sizes to-free))))))
 
-(with-temp-buffer
-  (insert-file-contents "input")
-  (solver-add-dir-size
-   (solver-parse-listing (split-string (buffer-string) "\n"))))
 
 (defun solver-parse-listing (lines)
   (cl-labels ((scan ()
@@ -62,7 +50,7 @@ $ ls
 
     (car (scan))))
 
-(defun solver-add-dir-size (tree)
+(defun solver-aggregate-size (tree)
   (cl-labels ((combiner (tri)
                         (list (car tri)
                               (adder tri)
@@ -79,9 +67,17 @@ $ ls
                                         (adder item))))
                                  (cdr tri) 0)))
 
-    (cl-loop for (_ size) on (flatten-tree (combiner tree)) by #'cddr
-             when (< size 100000)
-             sum size)))
+    (flatten-tree (combiner tree))))
+
+(defun solver-add-dir-size (sizes)
+  (cl-loop for (_ size) on sizes by #'cddr
+           when (< size 100000)
+           sum size))
+
+(defun solver-delete-what (sizes required)
+  (cl-loop for (_ size) on sizes by #'cddr
+           when (> size required)
+           minimizing size))
 
 (provide 'solver)
 ;;; solver.el ends here
-- 
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