## Problem Implement `max_l1_subarray_distance(a, b)` for two nonempty integer arrays. Choose one nonempty contiguous subarray from `a` and one nonempty contiguous subarray from `b`. The two chosen subarrays must have the same length. Their L1 distance is the sum of the absolute differences between corresponding elements. Return the maximum possible distance over every valid pair of subarrays. ## Constraints - `1 <= len(a), len(b) <= 2,000` - `-10^9 <= a[i], b[i] <= 10^9` - Length-one subarrays are valid. - Use integer arithmetic; the answer may exceed 32-bit range. ## Clarifications The two subarrays may start at different indices. Their common length may be any value from one through `min(len(a), len(b))`. Return only the maximum distance, not the subarray indices. ## Examples `a = [1, 3]`, `b = [2, 0]` returns `4`, obtained from both full arrays: `|1-2| + |3-0| = 4`. `a = [5]`, `b = [1, 9]` returns `4`. ## Hint Pairs of elements with a fixed difference between their indices lie on the same alignment diagonal. Consider what the best nonempty contiguous range on each such diagonal looks like when every contribution is nonnegative. ## Interview Follow-ups - Return the two start indices and the chosen length as well as the distance. - Explain the time and auxiliary-space complexity. - Discuss what changes if each aligned pair may contribute a negative score instead of an absolute difference.