feature: linked list cycle revisit

solairerove · Jan 15, 2024 · 1ef3fa1 · 1ef3fa1
1 parent cb807b9
commit 1ef3fa1
Showing 1 changed file with 5 additions and 1 deletion.
diff --git a/linked_list/LinkedListCycle.py b/linked_list/LinkedListCycle.py
@@ -7,9 +7,13 @@
 
 # O(n) time || O(1) space
 def has_cycle(self, head: Optional[ListNode]) -> bool:
-    slow = fast = head
+    if not head:
+        return False
+
+    slow, fast = head, head.next
     while fast and fast.next:
         slow, fast = slow.next, fast.next.next
+
         if slow == fast:
             return True