2765. Longest Alternating Subarray

You are given a 0-indexed integer array nums. A subarray s of length m is called alternating if: - m is greater than 1. - s1 = s0 + 1. - The 0-indexed subarray s looks like [s0, s1, s0, s1,...,s(m-1) % 2]. In other words, s1 - s0 = 1, s2 - s1 = -1, s3 - s2 = 1, s4 - s3 = -1, and so on up to s[m - 1] - s[m - 2] = (-1)m. Return the maximum length of all alternating subarrays present in nums or -