refactor

1 files changed, 9 insertions, 15 deletions

diff --git a/AoC2023/day08/solver.lisp b/AoC2023/day08/solver.lisp
index 0681e15..76001f1 100644
--- a/AoC2023/day08/solver.lisp
+++ b/AoC2023/day08/solver.lisp
@@ -18,21 +18,15 @@ ZZZ = (ZZZ, ZZZ)")
       (values instructions graph))))
 
 (defun traverse (instructions graph location terminatep)
-  (labels ((rec (steps)
-             (if (funcall terminatep location)
-                 (values steps location)
-                 (rec (+ steps (steps-needed)))))
-           (steps-needed ()
-             (loop
-               for direction across instructions
-               do (arrows:-<>
-                   (ecase direction
-                     (#\L #'first)
-                     (#\R #'second))
-                   (funcall <> (gethash location graph))
-                   (setf location <>))
-               count direction until (funcall terminatep location))))
-    (rec 0)))
+  (loop
+    for i from 0
+    do (arrows:-<>
+        (ecase (aref instructions (mod i (length instructions)))
+          (#\L #'first)
+          (#\R #'second))
+        (funcall <> (gethash location graph))
+        (setf location <>))
+    count i until (funcall terminatep location)))
 
 (defun solver1 (lines)
   (multiple-value-bind (instructions graph)