feat(content): function signatures + test cases

backend/data/questions/as-far-from-land-as-possible.yaml

@@ -10,6 +10,26 @@ patterns:
   - bfs
   - matrix-traversal
 
+function_signature: "def max_distance(grid: list[list[int]]) -> int:"
+
+test_cases:
+  visible:
+    - input: { grid: [[1, 0, 1], [0, 0, 0], [1, 0, 1]] }
+      expected: 2
+    - input: { grid: [[1, 0, 0], [0, 0, 0], [0, 0, 0]] }
+      expected: 4
+  hidden:
+    - input: { grid: [[1, 1, 1], [1, 1, 1], [1, 1, 1]] }
+      expected: -1
+    - input: { grid: [[0, 0, 0], [0, 0, 0], [0, 0, 0]] }
+      expected: -1
+    - input: { grid: [[1, 0], [0, 0]] }
+      expected: 2
+    - input: { grid: [[0, 0, 0], [0, 1, 0], [0, 0, 0]] }
+      expected: 2
+    - input: { grid: [[1, 1], [1, 0]] }
+      expected: 1
+
 description: |
   Given an `n x n` `grid` containing only values `0` and `1`, where `0` represents water and `1` represents land, find a water cell such that its distance to the nearest land cell is maximized, and return the distance.