Created attachment 582246 [details] [diff] [review]
It uses stdext::hash_set that is deprecated and, as such, is in __gnu_cxx namespace. Even after changing the namespace, it still fails to compile. Using std::unordered_set fixes the problem.
Comment on attachment 582246 [details] [diff] [review]
If this passes try, I'm fine with it.
Thanks for the review, pushed to m-i: