Count Number of Teams

You are given an integer array rating of size n, where rating[i] is the rating of the ith soldier.

A team consists of any three soldiers rating[i], rating[j], and rating[k] with i < j < k. A team is valid if:

rating[i] < rating[j] < rating[k] for teams of three, or rating[i] > rating[j] > rating[k] for teams of three.

Return the number of valid teams you can form.