3430. Maximum and Minimum Sums of at Most Size K Subarrays

You are given an integer array nums and a positive integer k. Return the sum of the maximum and minimum elements of all subarrays with at most k elements. Example 1: Input: nums = [1,2,3], k = 2 Output: 20 Explanation: The subarrays of nums with at most 2 elements are: Subarray Minimum Maximum Sum [1] 1 1 2 [2] 2 2 4 [3] 3 3 6 [1, 2] 1 2 3 [2, 3] 2 3 5 Final Total 20