3915. Maximum Sum of Alternating Subsequence With Distance at Least K

You are given an integer array nums of length n and an integer k. Pick a subsequence with indices 0 <= i1 < i2 < ... < im < n such that: - For every 1 <= t < m, it+1 - it >= k. - The selected values form a strictly alternating sequence. In other words, either: - nums[i1] < nums[i2] > nums[i3] < ..., or - nums[i1] > nums[i2] < nums[i3] > ... A subsequence of length 1 is also considered str