nextPermutation and ranges

[H. S. Teoh]

On Thu, Feb 07, 2013 at 09:42:34PM +0100, bearophile wrote:
> H. S. Teoh:
> 
> >Combinatorial puzzles come to mind (Rubik's cube solvers and its ilk,
> >for example).  Maybe other combinatorial problems that require some
> >kind of exhaustive state space search. Those things easily go past
> >20!  once you get beyond the most trivial cases.
> 
> I know many situations/problems where you have more than 20! cases,
> but in those problems you don't iterate all permutations, because the
> program takes ages to do it. In those programs you don't use
> nextPermutation, you scan the search space in a different and smarter
> way.
> 
> I don't know of any use case for permuting so large sets of items.
[...]

It depends, sometimes in complex cases you have no choice but to do
exhaustive search. I agree that it's very rare, though.


T

-- 
If creativity is stifled by rigid discipline, then it is not true creativity.