Java Sorting Algorithm

Question

Can anyone explain me this sentence please?

The sorting algorithm is a modified mergesort (in which the merge is omitted if the highest element in the low sublist is less than the lowest element in the high sublist).

Link: Arrays.sort(Object[] arr)

I know how Merge works, but I still don't understand well. Thank you.

Answer 1

Mergesort recursively merges sorted sublists. If the current sublists eligible for merging contain no overlapping elements, there's no need to merge them. The merge operation would be skipped.

Example:

List A
1 4 8 9

List B
10 12 14 19

There's no need to go through the process of comparing these lists because 9 is the largest element of A and 10 (the first element of B) is larger than the largest element of A. The result would just be the concatenation of A and B.

All the document is saying is that they take a shortcut if comprehensive processing is unnecessary.