38 lines
818 B
Python
38 lines
818 B
Python
def fibonacci(n: int) -> int:
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"""
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使用迭代方式计算第 n 个斐波那契数
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Args:
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n: 要计算的斐波那契数的位置（从 0 开始）
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Returns:
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第 n 个斐波那契数
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"""
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if n < 0:
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raise ValueError("n 必须是非负整数")
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if n == 0:
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return 0
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if n == 1:
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return 1
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prev, curr = 0, 1
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for _ in range(2, n + 1):
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prev, curr = curr, prev + curr
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return curr
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if __name__ == "__main__":
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# 测试代码
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print("斐波那契数列测试：")
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for i in range(10):
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print(f"F({i}) = {fibonacci(i)}")
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# 验证结果
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expected = [0, 1, 1, 2, 3, 5, 8, 13, 21, 34]
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for i in range(10):
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assert fibonacci(i) == expected[i], f"测试失败：F({i})"
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print("\n所有测试通过！")
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