Minimum Difference of K Scores

Sort to expose the best group

After sorting, evaluate every length-k window and minimize scores[i+k-1] - scores[i]. This works because if an optimal selected set contains two chosen values with an unchosen sorted value between them, replacing an extreme or filling that gap cannot increase the selected range. Thus some optimal set is a contiguous block in sorted order; there is no need to enumerate combinations.

Boundary cases

If k is one, the answer is zero. Validate k <= n before accessing a window, and use a wide integer if score differences can overflow a narrow signed type. Sorting takes O(n log n) time; the window scan is O(n); aside from the sorting implementation, extra space is O(1). Explain the distinction between minimizing max-minus-min and minimizing pairwise differences: for a chosen set, the former already equals its largest pairwise gap. Test duplicates, negative scores, k=n, and a set where the closest-looking values are not adjacent in original input order.