Sort one sequence by O(n) in time and O(1) in space
rosuav at gmail.com
Mon Feb 10 16:23:08 CET 2014
On Tue, Feb 11, 2014 at 2:03 AM, Sturla Molden <sturla.molden at gmail.com> wrote:
> Chris Angelico <rosuav at gmail.com> wrote:
>> That's assuming it really is a sort operation. The problem description
>> isn't entirely clear on this point, but if it's actually a zip, then
>> it can definitely be done in O(n).
> Ah, I didn't read it carefully enough. :-)
> Granted, a zip can be done in O(n) time and O(1) memory using a generator,
> which by the way is what itertools.izip does.
Right. I poked around in itertools but nothing was quite what I was
after, so I ended up writing my own generator. But it's still a zip
operation, and as such, is just a variant form of iterating over the
original list. All I do is follow a pattern other than the Red King's
"Begin at the beginning, go on till you come to the end, then raise
StopIteration" (or words to that effect).
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