23 May
2008
23 May
'08
6:33 p.m.
On Fri, 23 May 2008, Leif Walsh wrote:
I've worked this out (I'm sure I did this in intro CS once before...), although there is probably some optimization trick I'm missing, and I'm probably doing some silly double-allocation thing or something.
def combine(lists):
... if len(lists) is 0: ... return [[]] ... first = combine(lists[0:-1]) ... total = [] ... for item in lists[-1]: ... total += [[item] + subset for subset in first] ... return total
Oops, that should probably be:
... for subset in first: ... total += [subset + [item] for item in lists[-1]]
to maintain order. My excuse is that it's past my bedtime.
--
Cheers,
Leif