feat(content): function signatures + test cases

backend/data/questions/distinct-subsequences.yaml

@@ -9,6 +9,30 @@ categories:
 patterns:
   - dynamic-programming
 
+function_signature: "def num_distinct(s: str, t: str) -> int:"
+
+test_cases:
+  visible:
+    - input: { s: "rabbbit", t: "rabbit" }
+      expected: 3
+    - input: { s: "babgbag", t: "bag" }
+      expected: 5
+  hidden:
+    - input: { s: "a", t: "a" }
+      expected: 1
+    - input: { s: "a", t: "b" }
+      expected: 0
+    - input: { s: "aaa", t: "a" }
+      expected: 3
+    - input: { s: "aaa", t: "aa" }
+      expected: 3
+    - input: { s: "aaa", t: "aaa" }
+      expected: 1
+    - input: { s: "abc", t: "def" }
+      expected: 0
+    - input: { s: "abcde", t: "" }
+      expected: 1
+
 description: |
   Given two strings `s` and `t`, return *the number of distinct **subsequences** of* `s` *which equals* `t`.