feat(content): function signatures + test cases

backend/data/questions/airplane-seat-assignment-probability.yaml

@@ -9,6 +9,24 @@ categories:
 patterns:
   - dynamic-programming
 
+function_signature: "def nth_person_gets_nth_seat(n: int) -> float:"
+
+test_cases:
+  visible:
+    - input: { n: 1 }
+      expected: 1.0
+    - input: { n: 2 }
+      expected: 0.5
+  hidden:
+    - input: { n: 3 }
+      expected: 0.5
+    - input: { n: 10 }
+      expected: 0.5
+    - input: { n: 100 }
+      expected: 0.5
+    - input: { n: 1000 }
+      expected: 0.5
+
 description: |
   `n` passengers board an airplane with exactly `n` seats. The first passenger has lost their ticket and picks a seat randomly. After that, the rest of the passengers will: