38 lines
998 B
Python
38 lines
998 B
Python
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def find_unique_number(arr: list[int]) -> int:
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"""
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Given a list of integers where every element appears twice except for one,
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this function returns the element that appears only once using bitwise XOR.
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>>> find_unique_number([1, 1, 2, 2, 3])
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3
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>>> find_unique_number([4, 5, 4, 6, 6])
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5
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>>> find_unique_number([7])
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7
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>>> find_unique_number([10, 20, 10])
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20
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>>> find_unique_number([])
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Traceback (most recent call last):
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...
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ValueError: input list must not be empty
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>>> find_unique_number([1, 'a', 1])
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Traceback (most recent call last):
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...
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TypeError: all elements must be integers
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"""
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if not arr:
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raise ValueError("input list must not be empty")
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if not all(isinstance(x, int) for x in arr):
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raise TypeError("all elements must be integers")
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result = 0
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for num in arr:
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result ^= num
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return result
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if __name__ == "__main__":
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import doctest
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doctest.testmod()
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