Codility Dominator

Given a vector of integers, check if there is a dominator, meaning a value that occurs more than half the times, in it.

I have already written a couple of posts about this Codility problem. In the first one I solve it using a map as a buffer, in the second one I use the cheaper golden leader algorithm.

My porting to C++11 didn't change much of the original code. For instance, having to define a synonim to a type, instead of "typedef" it, I referred to the "using" keyword.