 The "n"-way mergesort algorithm also begins by distributing the list into "n" sublists and sorting each one; however, the sublists created by mergesort have overlapping value ranges and so cannot be recombined by simple concatenation as in bucket sort.Instead, they must be interleaved by a merge algorithm.However, this added expense is counterbalanced by the simpler scatter phase and the ability to ensure that each sublist is the same size, providing a good worst-case time bound.