aoc 2025 - still need to 7

Forgot to push these all onto the cloud lol

2025/puzzle-1.lisp

@@ -0,0 +1,40 @@
+(load "util.lisp")
+
+(defpackage "aoc:1"
+  (:use :cl "aoc-util"))
+
+(in-package "aoc:1")
+
+(fn round-1 (turns) (=> list fixnum)
+  (loop with dial = 50
+        with number-of-zeros = 0
+        for (rotation . magnitude) in turns
+        do (setf dial (mod (funcall rotation dial magnitude) 100))
+        if (= dial 0)
+          do (incf number-of-zeros)
+        finally (return number-of-zeros)))
+
+(fn round-2 (turns) (=> list fixnum)
+  (loop with dial = 50
+        with number-of-zeros = 0
+        for (rotation . magnitude) in turns
+        ;; FUCK I have to do this manually, too many edge cases
+        do (loop for i from 1 to magnitude
+                 for new-dial-value = (funcall rotation dial 1)
+                 if (or (= new-dial-value 0) (= new-dial-value 100))
+                   do (incf number-of-zeros)
+                 do (setf dial (mod new-dial-value 100)))
+        finally (return number-of-zeros)))
+
+(let ((turns (loop for line in (uiop:read-file-lines "1-input")
+                   for (rotation magnitude) = (->> line (split 1) multiple-value-list)
+                   collect (cons (if (string= rotation "L")
+                                     #'-
+                                     #'+)
+                                 (parse-integer* magnitude)))))
+  (->> turns
+       round-1
+       (format t "Round 1: ~a~%"))
+  (->> turns
+       round-2
+       (format t "Round 2: ~a~%")))