feat(content): function signatures + test cases

backend/data/questions/arranging-coins.yaml

@@ -9,6 +9,26 @@ categories:
 patterns:
   - binary-search
 
+function_signature: "def arrange_coins(n: int) -> int:"
+
+test_cases:
+  visible:
+    - input: { n: 5 }
+      expected: 2
+    - input: { n: 8 }
+      expected: 3
+  hidden:
+    - input: { n: 1 }
+      expected: 1
+    - input: { n: 3 }
+      expected: 2
+    - input: { n: 6 }
+      expected: 3
+    - input: { n: 10 }
+      expected: 4
+    - input: { n: 100 }
+      expected: 13
+
 description: |
   You have `n` coins and you want to build a staircase with these coins. The staircase consists of `k` rows where the i<sup>th</sup> row has exactly `i` coins. The last row of the staircase **may be** incomplete.