feat(content): function signatures + test cases

backend/data/questions/find-in-mountain-array.yaml

@@ -9,6 +9,30 @@ categories:
 patterns:
   - binary-search
 
+function_signature: "def find_in_mountain_array(target: int, mountain_arr: MountainArray) -> int:"
+
+test_cases:
+  visible:
+    - input: { mountain_arr: [1, 2, 3, 4, 5, 3, 1], target: 3 }
+      expected: 2
+    - input: { mountain_arr: [0, 1, 2, 4, 2, 1], target: 3 }
+      expected: -1
+  hidden:
+    - input: { mountain_arr: [1, 2, 3, 4, 5, 3, 1], target: 1 }
+      expected: 0
+    - input: { mountain_arr: [1, 2, 3, 4, 5, 3, 1], target: 5 }
+      expected: 4
+    - input: { mountain_arr: [1, 5, 2], target: 2 }
+      expected: 2
+    - input: { mountain_arr: [1, 5, 2], target: 1 }
+      expected: 0
+    - input: { mountain_arr: [1, 5, 2], target: 5 }
+      expected: 1
+    - input: { mountain_arr: [1, 2, 3, 4, 3, 2, 1], target: 0 }
+      expected: -1
+    - input: { mountain_arr: [0, 5, 3, 1], target: 0 }
+      expected: 0
+
 description: |
   *(This problem is an **interactive problem**.)*