Only need to do ii). As another example User 1 can rank the videos as 2,3,1,4 and User 2 as 1,3,2,4. In this case, their social distance would be 1 due to the (3,2) pair.

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 same videos using the sequence ul, U2, . . . , Un of numbers 1, 2, . . . , n, then their social distance is computed by counting all pairs (u,from the ranking of Tuo that satisfy the condition vi > vj for i