feat(content): function signatures + test cases

backend/data/questions/array-of-doubled-pairs.yaml

@@ -10,6 +10,32 @@ categories:
 patterns:
   - greedy
 
+function_signature: "def can_reorder_doubled(arr: list[int]) -> bool:"
+
+test_cases:
+  visible:
+    - input: { arr: [3, 1, 3, 6] }
+      expected: false
+    - input: { arr: [2, 1, 2, 6] }
+      expected: false
+    - input: { arr: [4, -2, 2, -4] }
+      expected: true
+  hidden:
+    - input: { arr: [1, 2, 4, 8] }
+      expected: true
+    - input: { arr: [0, 0] }
+      expected: true
+    - input: { arr: [0, 0, 0, 0] }
+      expected: true
+    - input: { arr: [-2, -4] }
+      expected: true
+    - input: { arr: [-1, -2, -4, -8] }
+      expected: true
+    - input: { arr: [1, 2, 1, 2] }
+      expected: true
+    - input: { arr: [1, 3] }
+      expected: false
+
 description: |
   Given an integer array of even length `arr`, return `true` *if it is possible to reorder* `arr` *such that* `arr[2 * i + 1] = 2 * arr[2 * i]` *for every* `0 <= i < len(arr) / 2`, *or* `false` *otherwise*.