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a9cee1d933
* Add perfect cube binary search algorithm * [pre-commit.ci] auto fixes from pre-commit.com hooks for more information, see https://pre-commit.ci * Add support for testing negative perfect cubes * Add TypeError check for invalid inputs * [pre-commit.ci] auto fixes from pre-commit.com hooks for more information, see https://pre-commit.ci --------- Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
56 lines
1.3 KiB
Python
56 lines
1.3 KiB
Python
def perfect_cube(n: int) -> bool:
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"""
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Check if a number is a perfect cube or not.
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>>> perfect_cube(27)
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True
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>>> perfect_cube(4)
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False
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"""
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val = n ** (1 / 3)
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return (val * val * val) == n
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def perfect_cube_binary_search(n: int) -> bool:
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"""
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Check if a number is a perfect cube or not using binary search.
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Time complexity : O(Log(n))
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Space complexity: O(1)
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>>> perfect_cube_binary_search(27)
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True
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>>> perfect_cube_binary_search(64)
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True
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>>> perfect_cube_binary_search(4)
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False
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>>> perfect_cube_binary_search("a")
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Traceback (most recent call last):
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...
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TypeError: perfect_cube_binary_search() only accepts integers
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>>> perfect_cube_binary_search(0.1)
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Traceback (most recent call last):
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...
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TypeError: perfect_cube_binary_search() only accepts integers
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"""
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if not isinstance(n, int):
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raise TypeError("perfect_cube_binary_search() only accepts integers")
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if n < 0:
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n = -n
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left = 0
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right = n
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while left <= right:
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mid = left + (right - left) // 2
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if mid * mid * mid == n:
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return True
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elif mid * mid * mid < n:
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left = mid + 1
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else:
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right = mid - 1
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return False
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if __name__ == "__main__":
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import doctest
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doctest.testmod()
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