feat(content): function signatures + test cases

backend/data/questions/build-array-from-permutation.yaml

@@ -8,6 +8,28 @@ categories:
 patterns:
   - matrix-traversal
 
+function_signature: "def build_array(nums: list[int]) -> list[int]:"
+
+test_cases:
+  visible:
+    - input: { nums: [0, 2, 1, 5, 3, 4] }
+      expected: [0, 1, 2, 4, 5, 3]
+    - input: { nums: [5, 0, 1, 2, 3, 4] }
+      expected: [4, 5, 0, 1, 2, 3]
+  hidden:
+    - input: { nums: [0] }
+      expected: [0]
+    - input: { nums: [1, 0] }
+      expected: [0, 1]
+    - input: { nums: [0, 1, 2, 3, 4] }
+      expected: [0, 1, 2, 3, 4]
+    - input: { nums: [4, 3, 2, 1, 0] }
+      expected: [0, 1, 2, 3, 4]
+    - input: { nums: [2, 0, 1] }
+      expected: [1, 2, 0]
+    - input: { nums: [3, 0, 2, 1] }
+      expected: [1, 3, 2, 0]
+
 description: |
   Given a **zero-based permutation** `nums` (**0-indexed**), build an array `ans` of the **same length** where `ans[i] = nums[nums[i]]` for each `0 <= i < nums.length` and return it.