feat(content): function signatures + test cases

backend/data/questions/check-if-all-integers-in-range-are-covered.yaml

@@ -9,6 +9,24 @@ categories:
 patterns:
   - prefix-sum
 
+function_signature: "def is_covered(ranges: list[list[int]], left: int, right: int) -> bool:"
+
+test_cases:
+  visible:
+    - input: { ranges: [[1, 2], [3, 4], [5, 6]], left: 2, right: 5 }
+      expected: true
+    - input: { ranges: [[1, 10], [10, 20]], left: 21, right: 21 }
+      expected: false
+  hidden:
+    - input: { ranges: [[1, 50]], left: 1, right: 50 }
+      expected: true
+    - input: { ranges: [[1, 2]], left: 1, right: 3 }
+      expected: false
+    - input: { ranges: [[1, 1], [3, 3]], left: 1, right: 3 }
+      expected: false
+    - input: { ranges: [[1, 5], [6, 10]], left: 1, right: 10 }
+      expected: true
+
 description: |
   You are given a 2D integer array `ranges` and two integers `left` and `right`. Each `ranges[i] = [start_i, end_i]` represents an **inclusive** interval between `start_i` and `end_i`.