34 lines
706 B
Python
34 lines
706 B
Python
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from lib_prime import get_divisors_count
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def euler_179_orig():
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r = 0
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for n in range(2, 10**7):
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if n % 10**5 == 0:
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print(n)
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if get_divisors_count(n) == get_divisors_count(n + 1):
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r += 1
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return r
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def euler_179():
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""" Much faster version. """
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upper = 10**7
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ndivs = [1 for _ in range(0, upper + 2)]
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for d in range(2, upper // 2):
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for i in range(d, upper + 2, d):
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ndivs[i] += 1
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r = 0
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for i in range(2, upper + 1):
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if ndivs[i] == ndivs[i + 1]:
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r += 1
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return r
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if __name__ == "__main__":
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solution = euler_179()
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print("e179.py: " + str(solution))
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assert(solution == 986262)
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