From a13bd02d72cea60d9218f716a83a2f1bb99500cf Mon Sep 17 00:00:00 2001
From: Oscar Najera <hi@oscarnajera.com>
Date: Sun, 3 Dec 2023 22:13:57 +0100
Subject: [AoC2023] day02 lisp

---
 AoC2023/day02/solver.lisp | 79 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 79 insertions(+)
 create mode 100644 AoC2023/day02/solver.lisp

(limited to 'AoC2023/day02/solver.lisp')

diff --git a/AoC2023/day02/solver.lisp b/AoC2023/day02/solver.lisp
new file mode 100644
index 0000000..60aa3cf
--- /dev/null
+++ b/AoC2023/day02/solver.lisp
@@ -0,0 +1,79 @@
+(ql:quickload '(uiop fiveam cl-ppcre))
+(defparameter eg-input "Game 1: 3 blue, 4 red; 1 red, 2 green, 6 blue; 2 green
+Game 2: 1 blue, 2 green; 3 green, 4 blue, 1 red; 1 green, 1 blue
+Game 3: 8 green, 6 blue, 20 red; 5 blue, 4 red, 13 green; 5 green, 1 red
+Game 4: 1 green, 3 red, 6 blue; 3 green, 6 red; 3 green, 15 blue, 14 red
+Game 5: 6 red, 1 blue, 3 green; 2 blue, 1 red, 2 green")
+
+(defun parse-set (info)
+  (let (list)
+    (cl-ppcre:do-register-groups ((#'parse-integer count) (#'read-from-string color))
+        ("(\\d+) (blue|red|green)" info)
+      (push (list color count) list))
+    list))
+
+(defun in-limits (max-red max-green max-blue)
+  (lambda (value)
+    (destructuring-bind (color count) value
+      (<= count
+          (ecase color
+            (red max-red)
+            (green max-green)
+            (blue max-blue))))))
+
+(defun parse-game (game-bounds)
+  (lambda (line)
+    (destructuring-bind (game . sets)
+        (uiop:split-string line :separator '(#\; #\:))
+      (if (every
+           (lambda (s)
+             (every game-bounds (parse-set s)))
+           sets)
+          (parse-integer (cl-ppcre:scan-to-strings "\\d+" game))
+          0))))
+
+(defun game-powers (line)
+  (apply #'* (mapcar #'cadr (parse-set (cdr (uiop:split-string line :separator '(#\; #\:)))))))
+
+(defun solve1 (lines bounds)
+  (reduce
+   #'+
+   lines
+   :key (parse-game bounds)))
+
+
+(defun max-set (top set)
+  (loop for (color count) in set do
+    (let ((var (ecase color
+                 (red 0)
+                 (green 1)
+                 (blue 2))))
+      (setf (elt top var) (max (elt top var) count))))
+  top)
+
+(defun solve2 (lines)
+  (apply #'+
+         (mapcar (lambda (line)
+                   (apply #'*
+                          (reduce #'max-set (cdr (uiop:split-string line :separator '(#\; #\:)))
+                                  :key #'parse-set
+                                  :initial-value (make-list 3 :initial-element 0))))
+                 lines)))
+
+(fiveam:test solutions
+  (fiveam:is
+   (= 8
+      (solve1
+       (uiop:split-string eg-input :separator '(#\Newline))
+       (in-limits 12 13 14))))
+  (fiveam:is
+   (= 2369
+      (solve1
+       (uiop:read-file-lines "input")
+       (in-limits 12 13 14))))
+  (fiveam:is
+   (= 2286
+      (solve2 (uiop:split-string eg-input :separator '(#\Newline)))))
+  (fiveam:is
+   (= 66363
+      (solve2 (uiop:read-file-lines "input")))))
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