I found this question at codility.com, but I don't understand the question. Can you help me figure out what do they want? I am more interested in the theory than a code.A non-empty zero-indexed array A consisting of N integers is given. A prefix_suffix_set is a pair of indices (P, S) such that 0  P, S < N and such that:every value that occurs in the sequence A[0], A[1], ..., A[P] also occurs in the sequence A[S], A[S + 1], ..., A[N  1],every value that occurs in the sequence A[S], A[S + 1], ..., A[N  1] also occurs in the sequence A[0], A[1], ..., A[P].The goal is to calculate the number of prefix_suffix_sets in the array. For example, consider array A such that:A[0] = 3A[1] = 5A[2] = 7A[3] = 3A[4] = 3A[5] = 5There are exactly fourteen prefix_suffix_sets: (1, 4), (1, 3), (2, 2), (2, 1), (2, 0), (3, 2), (3, 1), (3, 0), (4, 2), (4, 1), (4, 0), (5, 2), (5, 1), (5, 0).Write a function:function solution(A);that, given a non-empty zero-indexed array A of N integers, returns the number of prefix_suffix_sets.
help in theory regarding prefix_suffix_set
algorithms