Definition: Randomly permute N elements by exchanging each element ei with a random element from i to N. It consumes Θ(N log N) bits and runs in linear time.
Generalization (I am a kind of ...)
ideal random shuffle, permutation.
See also Johnson-Trotter, pseudo-random number generator.
Note: The algorithm can be viewed as a reverse selection sort. It is described in some detail as algorithm 3.4.2P in [Knuth97, 2:145].
For even a rather small number of elements (or cards), the total number of permutations is far larger than the period of most pseudo-random number generators. This implies that most permutations will never be generated. (After documentation for random.shuffle() in Python, particularly v2.6.1.)
R. A. Fisher and F. Yates, Example 12, Statistical Tables, London, 1938.
Richard Durstenfeld, Algorithm 235: Random permutation, CACM 7(7):420, July 1964.
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Entry modified 23 May 2011.
HTML page formatted Tue Dec 6 16:16:32 2011.
Cite this as:
Paul E. Black, "Fisher-Yates shuffle", in Dictionary of Algorithms and Data Structures [online], Paul E. Black, ed., U.S. National Institute of Standards and Technology. 23 May 2011. (accessed TODAY) Available from: http://www.nist.gov/dads/HTML/fisherYatesShuffle.html