{
  "topic": "example-topic",
  "type": "code_reading",
  "schema_version": "1.0.0",
  "generated": "2026-01-01T00:00:00Z",
  "questions": [
    {
      "id": "dom-sub-top-cr-001",
      "type": "code_reading",
      "difficulty": 4,
      "tags": ["example", "template", "javascript"],
      "question": "阅读以下 JavaScript 代码，回答子问题。",
      "code": "function fibonacci(n) {\n  if (n <= 1) return n;\n  let a = 0, b = 1;\n  for (let i = 2; i <= n; i++) {\n    [a, b] = [b, a + b];\n  }\n  return b;\n}\n\nconsole.log(fibonacci(6));",
      "language": "javascript",
      "sub_questions": [
        {
          "index": 1,
          "type": "short_answer",
          "question": "这段代码的输出是什么？",
          "answer": "8",
          "explanation": "fibonacci(6) 的计算过程：f(0)=0, f(1)=1, f(2)=1, f(3)=2, f(4)=3, f(5)=5, f(6)=8。最终输出 8。"
        },
        {
          "index": 2,
          "type": "single_choice",
          "question": "该算法的时间复杂度是什么？",
          "options": {
            "A": "O(1)",
            "B": "O(n)",
            "C": "O(n^2)",
            "D": "O(2^n)"
          },
          "answer": "B",
          "explanation": "该实现使用迭代方式，for 循环执行 n-1 次，每次操作是常数时间，因此时间复杂度为 O(n)。"
        }
      ],
      "explanation": "这段代码实现了斐波那契数列的迭代求解。与递归实现相比，迭代版本避免了重复计算，时间复杂度从 O(2^n) 降低到 O(n)，空间复杂度为 O(1)。",
      "source": null,
      "related": []
    }
  ]
}