hard split, easy merge

(algorithmic technique)

Definition: A recursive algorithm, especially a sort algorithm, where dividing (splitting) into smaller problems is time consuming or complex and combining (merging) the solutions is quick or trivial.

Generalization (I am a kind of ...)
divide and conquer.

Aggregate parent (I am a part of or used in ...)
radix sort, quicksort, bucket sort, selection sort.

See also easy split, hard merge.

Note: Although the notion is wide spread, I first heard this term from Doug Edwards about 1994.

Called "Conquer form" of using divide and conquer in [ATCH99, page 3-3].

Author: PEB

Go to the Dictionary of Algorithms and Data Structures home page.

If you have suggestions, corrections, or comments, please get in touch with Paul Black.

Entry modified 27 October 2005.
HTML page formatted Mon Feb 2 13:10:39 2015.

Cite this as:
Paul E. Black, "hard split, easy merge", in Dictionary of Algorithms and Data Structures [online], Vreda Pieterse and Paul E. Black, eds. 27 October 2005. (accessed TODAY) Available from: