LeetCode-141: Linked List Cycle(set)

Author: WazedKhan

prep/practice/linked_list.py

@@ -46,3 +46,12 @@ def mergeTwoLists(self, list1: Optional[ListNode], list2: Optional[ListNode]) ->
             tail.next = list2
 
         return dummy.next
+
+    def hasCycle(self, head: Optional[ListNode]) -> bool:
+        seen = set()
+        while head:
+            if head in seen:
+                return True
+            seen.add(head)
+            head = head.next
+        return False