From d0bd893f59a12fd3b58eaf998a2fc48e7b90e975 Mon Sep 17 00:00:00 2001
From: Oscar Najera <hi@oscarnajera.com>
Date: Thu, 14 Dec 2023 10:31:32 +0100
Subject: [AoC2023] day11 part 1 lisp

---
 AoC2023/day11/solver.lisp | 66 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 66 insertions(+)
 create mode 100644 AoC2023/day11/solver.lisp

(limited to 'AoC2023/day11/solver.lisp')

diff --git a/AoC2023/day11/solver.lisp b/AoC2023/day11/solver.lisp
new file mode 100644
index 0000000..e7feabf
--- /dev/null
+++ b/AoC2023/day11/solver.lisp
@@ -0,0 +1,66 @@
+;; 9:59
+;; 10:31 part1
+;;
+(ql:quickload '(fiveam))
+(defparameter eg-input "...#......
+.......#..
+#.........
+..........
+......#...
+.#........
+.........#
+..........
+.......#..
+#...#.....")
+
+(defun indexes (array)
+  (loop for v across array
+        for i from 0 when v collect i))
+
+(defun shift (coord spacers)
+  (count-if (lambda (idx) (< idx coord)) spacers))
+
+(defun expanded (point free-rows free-cols)
+  (destructuring-bind (y x) point
+    (list (+ y (shift y free-rows))
+          (+ x (shift x free-cols)))))
+
+(fiveam:test parts
+  (fiveam:is (= 1 (shift 5 '(3 6))))
+  (fiveam:is (equal '(7 4) (expanded '(5 3) '(1 2) '(2)))))
+
+(defun expanded-galaxies (rows)
+  (let* ((free-rows (make-array (length rows) :initial-element t))
+         (free-cols (make-array (length (car rows)) :initial-element t))
+         (galaxies (loop for row in rows
+                         for y from 0
+                         nconc
+                         (loop for col across row
+                               for x from 0
+                               when (eq col #\#)
+                                 collect (list y x)
+                                 and do (setf (aref free-rows y) nil
+                                              (aref free-cols x) nil)))))
+    (map 'vector
+         (lambda (galaxie)
+           (expanded galaxie
+                     (indexes free-rows)
+                     (indexes free-cols)))
+         galaxies)))
+
+
+(defun manhattan-dist (s x)
+  (destructuring-bind ((sx  sy) (bx  by)) (list s x)
+    (+ (abs (- bx sx)) (abs (- by sy)))))
+
+
+(defun solver1 (rows)
+  (loop with gals = (expanded-galaxies rows)
+        for g across gals
+        for i from 0 sum
+                     (loop for j from (1+ i) below (length gals)
+                           sum (manhattan-dist g (aref gals j)))))
+
+(fiveam:test solutions
+  (fiveam:is (= 374 (solver1 (uiop:split-string eg-input :separator '(#\Newline)))))
+  (fiveam:is (= 10154062 (solver1 (uiop:read-file-lines "input")))))
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