Definition: Merge n sorted streams into one output stream. To begin the streams are sorted by the value of the head element of each. Then the head of the first stream, which is the least since the streams were sorted, is removed and written to the output. That stream is inserted back into the list of streams according to its new head. Taking the head of the first stream and reinserting that stream is repeated until all elements have been processed. Using linear search to insert a stream into the list, the execution time is Θ(M N) where M is the total number of elements. Keeping the streams in a heap, the execution time is Θ(M log N).
See also simple merge, optimal merge, UnShuffle sort, merge sort.
Note: Ideal merge was first mentioned by Art S. Kagel as part of the implementation of the UnShuffle sort.
If you have suggestions, corrections, or comments, please get in touch with Paul Black.
Entry modified 9 January 2009.
HTML page formatted Mon Feb 2 13:10:39 2015.
Cite this as:
Art S. Kagel, "ideal merge", in Dictionary of Algorithms and Data Structures [online], Vreda Pieterse and Paul E. Black, eds. 9 January 2009. (accessed TODAY) Available from: http://www.nist.gov/dads/HTML/idealmerge.html