46 lines
823 B
Python
46 lines
823 B
Python
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#! /usr/local/python
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# Factorize numbers, slowly.
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# This version uses plain integers and is thus limited to 2**31-1.
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import sys
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from math import sqrt
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error = 'fact.error' # exception
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def fact(n):
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if n < 1: raise error # fact() argument should be >= 1
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if n = 1: return [] # special case
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res = []
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# Treat even factors special, so we can use i = i+2 later
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while n%2 = 0:
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res.append(2)
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n = n/2
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# Try odd numbers up to sqrt(n)
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limit = int(sqrt(float(n+1)))
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i = 3
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while i <= limit:
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if n%i = 0:
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res.append(i)
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n = n/i
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limit = int(sqrt(float(n+1)))
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else:
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i = i+2
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res.append(n)
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return res
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def main():
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if len(sys.argv) > 1:
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for arg in sys.argv[1:]:
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n = int(eval(arg))
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print n, fact(n)
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else:
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try:
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while 1:
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n = int(input())
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print n, fact(n)
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except EOFError:
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pass
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main()
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