feat(content): more test cases

backend/data/questions/linked-list-cycle.yaml

@@ -10,6 +10,24 @@ categories:
 patterns:
   - fast-slow-pointers
 
+function_signature: "def has_cycle(head: ListNode | None) -> bool:"
+
+test_cases:
+  visible:
+    - input: { head: [3, 2, 0, -4], pos: 1 }
+      expected: true
+    - input: { head: [1, 2], pos: 0 }
+      expected: true
+    - input: { head: [1], pos: -1 }
+      expected: false
+  hidden:
+    - input: { head: [], pos: -1 }
+      expected: false
+    - input: { head: [1, 2, 3, 4, 5], pos: -1 }
+      expected: false
+    - input: { head: [1, 2, 3, 4, 5], pos: 4 }
+      expected: true
+
 description: |
   Given `head`, the head of a linked list, determine if the linked list has a cycle in it.