Only need to do ii).

Video rankings. The InstaVid social network collects user preferences by ask- ing them to rank their favorite videos. One of the features of InstaVid is offering friendship suggestions for users with similar tastes, using the following metric. If user One ranks the videos using the sequence 1,2,... n, and user Two ranks same videos using the sequence v1, v2,... , Vn of numbers 1,2,...,n, then their social distance is computed by counting all pairs (vi, vj) from the ranking of Two that satisfy the condition vi Uj for i