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9200a2e543
* from __future__ import annotations
* fixup! from __future__ import annotations
* fixup! from __future__ import annotations
* fixup! Format Python code with psf/black push
Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
53 lines
1.1 KiB
Python
53 lines
1.1 KiB
Python
"""
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python/black : True
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"""
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from __future__ import annotations
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def prime_factors(n: int) -> list[int]:
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"""
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Returns prime factors of n as a list.
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>>> prime_factors(0)
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[]
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>>> prime_factors(100)
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[2, 2, 5, 5]
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>>> prime_factors(2560)
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[2, 2, 2, 2, 2, 2, 2, 2, 2, 5]
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>>> prime_factors(10**-2)
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[]
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>>> prime_factors(0.02)
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[]
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>>> x = prime_factors(10**241) # doctest: +NORMALIZE_WHITESPACE
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>>> x == [2]*241 + [5]*241
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True
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>>> prime_factors(10**-354)
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[]
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>>> prime_factors('hello')
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Traceback (most recent call last):
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...
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TypeError: '<=' not supported between instances of 'int' and 'str'
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>>> prime_factors([1,2,'hello'])
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Traceback (most recent call last):
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...
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TypeError: '<=' not supported between instances of 'int' and 'list'
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"""
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i = 2
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factors = []
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while i * i <= n:
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if n % i:
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i += 1
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else:
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n //= i
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factors.append(i)
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if n > 1:
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factors.append(n)
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return factors
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if __name__ == "__main__":
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import doctest
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doctest.testmod()
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