39 lines
947 B
Python
39 lines
947 B
Python
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#!/usr/bin/env python3
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def main(lim): #exclusive lim
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primes = get_primes(bound(lim, 2))
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nums = [True] * lim
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c = 0
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fb = bound(lim, 4)
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for frth in primes:
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if frth > fb:
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break
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cb = bound(lim-frth**4, 3)
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for cube in primes:
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if cube > cb:
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break
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sb = bound(lim - frth**4 - cube**3, 2)
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for sq in primes:
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if sq > sb:
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break
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n = frth**4 + cube**3 + sq**2
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c += nums[n]
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nums[n] = False
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return c
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def bound(lim, pw):
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return int(lim**(1.0/pw))
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def get_primes(lim): #inclusive lim
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sieve = [False]*2 + [True] * (lim-1)
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p = []
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for i in range(2, len(sieve)):
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if sieve[i]:
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p.append(i)
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for j in range(2*i, len(sieve), i):
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sieve[j] = False
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return p
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#print(main(50))
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print(main(50*10**6))
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