feat(content): function signatures + test cases

backend/data/questions/avoid-flood-in-the-city.yaml

@@ -10,6 +10,28 @@ patterns:
   - greedy
   - binary-search
 
+function_signature: "def avoid_flood(rains: list[int]) -> list[int]:"
+
+test_cases:
+  visible:
+    - input: { rains: [1, 2, 3, 4] }
+      expected: [-1, -1, -1, -1]
+    - input: { rains: [1, 2, 0, 0, 2, 1] }
+      expected: [-1, -1, 2, 1, -1, -1]
+    - input: { rains: [1, 2, 0, 1, 2] }
+      expected: []
+  hidden:
+    - input: { rains: [1, 0, 1] }
+      expected: [-1, 1, -1]
+    - input: { rains: [0, 1, 1] }
+      expected: []
+    - input: { rains: [1, 1] }
+      expected: []
+    - input: { rains: [0] }
+      expected: [1]
+    - input: { rains: [1] }
+      expected: [-1]
+
 description: |
   Your country has an infinite number of lakes. Initially, all the lakes are empty, but when it rains over the n<sup>th</sup> lake, that lake becomes full of water. If it rains over a lake that is **full of water**, there will be a **flood**.