@@ -47,6 +47,46 @@ def prime_factors(n: int) -> list[int]:
4747 return factors
4848
4949
50+ def unique_prime_factors (n : int ) -> list [int ]:
51+ """
52+ Returns unique prime factors of n as a list.
53+
54+ >>> unique_prime_factors(0)
55+ []
56+ >>> unique_prime_factors(100)
57+ [2, 5]
58+ >>> unique_prime_factors(2560)
59+ [2, 5]
60+ >>> unique_prime_factors(10**-2)
61+ []
62+ >>> unique_prime_factors(0.02)
63+ []
64+ >>> unique_prime_factors(10**241)
65+ [2, 5]
66+ >>> unique_prime_factors(10**-354)
67+ []
68+ >>> unique_prime_factors('hello')
69+ Traceback (most recent call last):
70+ ...
71+ TypeError: '<=' not supported between instances of 'int' and 'str'
72+ >>> unique_prime_factors([1,2,'hello'])
73+ Traceback (most recent call last):
74+ ...
75+ TypeError: '<=' not supported between instances of 'int' and 'list'
76+ """
77+ i = 2
78+ factors = []
79+ while i * i <= n :
80+ if not n % i :
81+ while not n % i :
82+ n //= i
83+ factors .append (i )
84+ i += 1
85+ if n > 1 :
86+ factors .append (n )
87+ return factors
88+ 89+ 5090if __name__ == "__main__" :
5191 import doctest
5292
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