Big-O notation (was: Re: Python and Schools)
David Eppstein
eppstein at ics.uci.edu
Tue Apr 15 22:10:40 EDT 2003
In article <b7id3q$3s4$1 at news.hccnet.nl>,
anton at vredegoor.doge.nl (Anton Vredegoor) wrote:
> >Also, one further class that is import to know is O( 2**N ), such as the
> >brute-force solution to the "travelling salesman problem". These are
>
> Although it's important to not set too severe limitations I have the
> impression this salesman is underestimating the problem.
>
> >>> def fac(n):
> ... return reduce(operator.mul,range(2,n+1),1)
> ...
> >>> fac(10)
> 3628800
> >>> 2**10
> 1024
Actually, it's possible to solve the traveling salesman problem in time
O(n 2^n), much better than factorial. But the solution involves dynamic
programming and is probably not what Chad N. meant by "brute-force".
--
David Eppstein http://www.ics.uci.edu/~eppstein/
Univ. of California, Irvine, School of Information & Computer Science
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