24 lines
716 B
Python
24 lines
716 B
Python
from math import sqrt
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from itertools import imap, ifilter, islice, count
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def factor_pairs(n):
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return ((x, n // x) for x in xrange(2, int(sqrt(n))) if n % x == 0)
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def fangs(n):
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dlen = lambda x: len(str(x))
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half = dlen(n) // 2
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digits = lambda (x, y): sorted(str(x) + str(y))
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halvesQ = lambda xs: all(y == half for y in imap(dlen, xs))
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dn = sorted(str(n))
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return [p for p in factor_pairs(n) if halvesQ(p) and dn==digits(p)]
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def vampiricQ(n):
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fn = fangs(n)
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return (n, fn) if fn else None
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for v in islice(ifilter(None, imap(vampiricQ, count())), 0, 25):
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print v
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for n in [16758243290880, 24959017348650, 14593825548650]:
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print vampiricQ(n) or str(n) + " is not vampiric."
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