Write C code for a getCommonNeighbors function that accepts two vertex struct pointers, u and v, and returns unordered_set containing the IDs of all vertices that are neighbors to both u and v. You may use the set_intersection function in the library, which calculates the intersection of two sets when given 5 iterators (left begin, left end, right begin, right end, and output), though using unordered_set::count or unordered_set::find may be easier.