On 8/11/14, 6:55 AM, Ary Borenszweig wrote:
On 8/11/14, 12:29 AM, Andrei Alexandrescu wrote:
Hello,
In which algorithms would one use std::rotate?
Depends on whom you ask :o). I think it's a fairly obscure algorithm,
better suited as representative of a class rather than frequently
useful. Facebook's C++ code base only has few uses, all in the same
pattern rotate(b, b + 1, e) i.e. bubble the front all the way to the
back with random iterators. (The result is not used and is trivially e - 1.)
(One frequent use is in ranges/iterators debates; out of the woodwork
come people whose livelihood apparently depends on rotate, in particular
on using rotate with non-random iterators (random access ranges make it
easy to implement) AND needing the result.)
I do think that, like partition or partialSort, std::rotate is one of
those algorithms that's good to know about because it may save some
otherwise awkward solutions. Sean Parent has a nice talk
http://channel9.msdn.com/Events/GoingNative/2013/Cpp-Seasoning on such.
For my money I think http://dpaste.dzfl.pl/a0effbaee0a9 is fine (after
being of course productionized to take advantage of random access if
available, improve on the recursion, etc). Requiring sameHead or random
access seems to me a good sweet spot.
Andrei
