30 lines
660 B
Python
30 lines
660 B
Python
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#From: https://stackoverflow.com/questions/17298130/working-with-large-primes-in-python
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from random import randrange
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def is_prime(n, k=10):
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if n == 2:
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return True
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if not n & 1:
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return False
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def check(a, s, d, n):
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x = pow(a, d, n)
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if x == 1:
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return True
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for i in range(s - 1):
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if x == n - 1:
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return True
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x = pow(x, 2, n)
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return x == n - 1
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s = 0
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d = n - 1
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while d % 2 == 0:
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d >>= 1
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s += 1
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for i in range(k):
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a = randrange(2, n - 1)
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if not check(a, s, d, n):
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return False
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return True
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