feat: week9 - linked list cycle

Author: Seoya0512

linked-list-cycle/Seoya0512.py

@@ -0,0 +1,10 @@
+class Solution:
+    def hasCycle(self, head: Optional[ListNode]) -> bool:
+        cycle_set = set()
+        while head:
+            if head in cycle_set:
+                return True
+            cycle_set.add(head)
+            head = head.next
+        return False
+