elegant way to remove all elements of a vector that are contained in another vector?

Question

While looking over some code I found loopy and algorithmically slow implementation of std::set_difference :

 for(int i = 0; i < a.size(); i++)
 {
  iter = std         


        

Answer 1

One solution that comes to mind is combining remove_if and binary_search. It's effectively the same as your manual looping solution but might be a bit more "elegant" as it uses more STL features.

sort(begin(b), end(b));
auto iter = remove_if(begin(a), end(a), 
                      [](auto x) { 
                          return binary_search(begin(b), end(b), x); 
                      });
// Now [begin(a), iter) defines a new range, and you can erase them however
// you see fit, based on the type of a.