feat(content): function signatures + test cases

backend/data/questions/all-paths-from-source-to-target.yaml

@@ -10,6 +10,24 @@ patterns:
   - dfs
   - backtracking
 
+function_signature: "def all_paths_source_target(graph: list[list[int]]) -> list[list[int]]:"
+
+test_cases:
+  visible:
+    - input: { graph: [[1, 2], [3], [3], []] }
+      expected: [[0, 1, 3], [0, 2, 3]]
+    - input: { graph: [[4, 3, 1], [3, 2, 4], [3], [4], []] }
+      expected: [[0, 4], [0, 3, 4], [0, 1, 3, 4], [0, 1, 2, 3, 4], [0, 1, 4]]
+  hidden:
+    - input: { graph: [[1], []] }
+      expected: [[0, 1]]
+    - input: { graph: [[1, 2, 3], [4], [4], [4], []] }
+      expected: [[0, 1, 4], [0, 2, 4], [0, 3, 4]]
+    - input: { graph: [[2, 1], [2], []] }
+      expected: [[0, 2], [0, 1, 2]]
+    - input: { graph: [[1, 3], [2], [3], []] }
+      expected: [[0, 1, 2, 3], [0, 3]]
+
 description: |
   Given a directed acyclic graph (**DAG**) of `n` nodes labeled from `0` to `n - 1`, find all possible paths from node `0` to node `n - 1` and return them in **any order**.