24 lines
469 B
Python
24 lines
469 B
Python
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import math
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# some utility functions, same as above
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def is_square(x):
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return int(math.sqrt(x)) == math.sqrt(x)
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primes = {}
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def is_prime(x):
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try:
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return primes[x]
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except KeyError:
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if x < 2:
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primes[x] = False
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return False
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i = 2
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while i * i <= x:
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if x % i == 0:
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primes[x] = False
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return False
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i += 1
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primes[x] = True
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return True
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