2024 day 3

2024/3/main.lisp

@@ -0,0 +1,28 @@
+(asdf:load-system :cl-ppcre)
+
+(defun solve-1 (line)
+  (let ((result 0))
+    (ppcre:do-register-groups (a b)
+        ("mul\\(([0-9]+),([0-9]+)\\)" line result)
+      (incf result (* (parse-integer a) (parse-integer b))))))
+
+(defun solve-2 (line)
+  (let ((result 0)
+        (enabled t))
+    (ppcre:do-register-groups (mul a b dop dontp)
+        ("(mul\\(([0-9]+),([0-9]+)\\))|(do\\(\\))|(don't\\(\\))" line result)
+      (declare (ignore mul))
+      (cond
+        (dop
+         (setf enabled t))
+        (dontp
+         (setf enabled nil))
+        (enabled
+         (incf result (* (parse-integer a) (parse-integer b))))))))
+
+(defun main ()
+  (let ((input (uiop:read-file-string "data.txt")))
+    (format t
+            "1: ~A~%2: ~A~%"
+            (solve-1 input)
+            (solve-2 input))))