feat(content): function signatures + test cases

backend/data/questions/island-perimeter.yaml

@@ -9,6 +9,30 @@ categories:
 patterns:
   - matrix-traversal
 
+function_signature: "def island_perimeter(grid: list[list[int]]) -> int:"
+
+test_cases:
+  visible:
+    - input: { grid: [[0, 1, 0, 0], [1, 1, 1, 0], [0, 1, 0, 0], [1, 1, 0, 0]] }
+      expected: 16
+    - input: { grid: [[1]] }
+      expected: 4
+    - input: { grid: [[1, 0]] }
+      expected: 4
+  hidden:
+    - input: { grid: [[1, 1]] }
+      expected: 6
+    - input: { grid: [[1], [1]] }
+      expected: 6
+    - input: { grid: [[1, 1], [1, 1]] }
+      expected: 8
+    - input: { grid: [[0, 1, 0], [1, 1, 1], [0, 1, 0]] }
+      expected: 12
+    - input: { grid: [[1, 1, 1, 1, 1]] }
+      expected: 12
+    - input: { grid: [[0, 0, 0], [0, 1, 0], [0, 0, 0]] }
+      expected: 4
+
 description: |
   You are given a `row x col` grid representing a map where `grid[i][j] = 1` represents land and `grid[i][j] = 0` represents water.