bidirectional bubble sort


Definition: A variant of bubble sort that compares each adjacent pair of items in a list in turn, swapping them if necessary, and alternately passes through the list from the beginning to the end then from the end to the beginning. It stops when a pass does no swaps.

Also known as cocktail shaker sort, shaker sort, double-direction bubble sort.

Generalization (I am a kind of ...)

See also bubble sort, gnome sort.

Note: Complexity is O(n2) for arbitrary data, but approaches O(n) if the list is nearly in order at the beginning. Bidirectional bubble sort usually does better than bubble sort since at least one item is moved forward or backward to its place in the list with each pass. Bubble sort moves items forward into place, but can only move items backward one location each pass.

Authors: PEB,BB


Pat Morin's implementation, see cocktail sort (Java). (Python).
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Entry modified 21 April 2022.
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Cite this as:
Paul E. Black and Bob Bockholt, "bidirectional bubble sort", in Dictionary of Algorithms and Data Structures [online], Paul E. Black, ed. 21 April 2022. (accessed TODAY) Available from: