Remove algorithms implementation duplications

[Marc Glisse]

On Thu, 19 Jul 2012, François Dumont wrote:

>    Sorry if you find this feedback rather light, I do not have the same C++ 
> background as other libstdc++ maintainers, I feel what I do more than I can 
> explain it.

Oh, no, that was great feedback (I'll re-read it at a quiter time), thanks 
a lot for taking the time to write it :-)

-- 
Marc Glisse