Minimum Length Subarray with K Distinct Numbers

Given an integer list and `k`, return the minimum subarray length containing exactly or at least `k` distinct numbers, or `-1` when no such subarray exists. Requirements Function: getMinLengthSubarray(arr, k). Input: List<Integer> arr and integer k. Output: minimum qualifying subarray length, or -1 if no qualifying subarray exists. The prompt centres on maintaining a num -> frequency map with a sliding window. Notes Expand the right pointer and update the frequency map and distinct count. While the current window satisfies the distinct-count condition, update the best length and shrink from the left. Clarify whether the condition is exactly k distinct or at least k distinct. The sliding-window skeleton is the same, but the shrink condition differs slightly. Preparation Code the at-least-k variant first: expand right, then shrink while the window remains valid, updating the minimum length before each shrink. Prepare a one-sentence clarification for exactly-k vs at-least-k; if it is exactly k, shrink when distinct exceeds k and update only when distinct equals k.