feat(content): function signatures + test cases

backend/data/questions/average-waiting-time.yaml

@@ -8,6 +8,26 @@ categories:
 patterns:
   - greedy
 
+function_signature: "def average_waiting_time(customers: list[list[int]]) -> float:"
+
+test_cases:
+  visible:
+    - input: { customers: [[1, 2], [2, 5], [4, 3]] }
+      expected: 5.0
+    - input: { customers: [[5, 2], [5, 4], [10, 3], [20, 1]] }
+      expected: 3.25
+  hidden:
+    - input: { customers: [[1, 1]] }
+      expected: 1.0
+    - input: { customers: [[1, 5], [2, 3], [3, 2]] }
+      expected: 5.0
+    - input: { customers: [[1, 1], [2, 1], [3, 1]] }
+      expected: 1.0
+    - input: { customers: [[1, 10], [1, 10], [1, 10]] }
+      expected: 20.0
+    - input: { customers: [[10, 5], [20, 5], [30, 5]] }
+      expected: 5.0
+
 description: |
   There is a restaurant with a single chef. You are given an array `customers`, where `customers[i] = [arrival_i, time_i]`: