Maximum Frequency Score of a Subarray

Given an integer array, find the contiguous subarray that maximizes a score defined by element frequencies (a function of each element's count within the subarray). The challenge is to evaluate that score for all subarrays efficiently by incrementally maintaining counts and the aggregated score using hash maps plus an ordered/multiset or Fenwick/segment-tree structure (or a clever two-pointer/online strategy) to avoid O(n^2) brute force.