You are given an integer array nums and a positive integer k.

The frequency score of a subarray is defined as the sum of $v^c$ across all distinct values $v$ present in the subarray, where $c$ denotes the number of occurrences of $v$ in that subarray.

Return the maximum frequency score achievable among all subarrays of length k. Since the resulting value may be large, return it modulo $10^9 + 7$.

Note: A subarray is a contiguous sequence of elements within an array.

Constraints:

• $1 \leq$ k $\leq$ nums.length $\leq 10^5$

• $1 \leq$ nums[i] $\leq 10^6$

Now, let’s take a moment to make sure you’ve correctly understood the problem. The quiz below helps you check if you’re solving the correct problem:

We have a game for you to play. Rearrange the logical building blocks to develop a clearer understanding of how to solve this problem.

Implement your solution in the following coding playground.