Desafío 2012-06 El problema de Hamming

hamming.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
#       hamming.py
#       
#       Copyright 2012 Javier Rovegno Campos <javier.rovegno@gmail.com>
#       
#       This program is free software; you can redistribute it and/or modify
#       it under the terms of the GNU General Public License as published by
#       the Free Software Foundation; either version 2 of the License, or
#       (at your option) any later version.
#       
#       This program is distributed in the hope that it will be useful,
#       but WITHOUT ANY WARRANTY; without even the implied warranty of
#       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#       GNU General Public License for more details.
#       
#       You should have received a copy of the GNU General Public License
#       along with this program; if not, write to the Free Software
#       Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
#       MA 02110-1301, USA.

import sys

def H(p1, p2, p3, i):
    """
    >>> H(2,3,5,5)
    6
    >>> H(2,3,5,9)
    12
    >>> H(7,13,19,100)
    26590291
    """
    p1, p2, p3, i = int(p1), int(p2), int(p3), int(i)
    binomial = [120, 1140, 4060, 9880, 19600, 
                34220, 54740, 82160, 117480, 
                161700, 215820, 280840, 357760]
    combina = 0
    for val in binomial:
        combina += 10
        if val > i:
            break
    s = range(combina)
    p = [[k,l,m] for k in s for l in s for m in s]
    aux = []
    for j in p:
        aux.append(p1**j[0] * p2**j[1] * p3**j[2])
    aux.sort()
    return aux[i]


def test():
    import doctest
    doctest.testmod()

def main():
    try:
        args = sys.argv[1:]
        print H(args[0], args[1], args[2], args[3])
    except:
        print "Use: python hamming.py 7 13 19 100"

if __name__ == '__main__':
    main()