AN ANALYSIS OF A SIMPLE ALGORITHM FOR RANDOM DERANGEMENTS
AN ANALYSIS OF A SIMPLE ALGORITHM FOR RANDOM DERANGEMENTS
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一种简单的随机排列算法分析
DOI:
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发表时间:
2007
期刊:
影响因子:
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通讯作者:
M. Verri
中科院分区:
文献类型:
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作者:
D. Merlini;R. Sprugnoli;M. Verri
We consider the uniform generation of random derangements, i.e., permutations without any fixed point. By using a rejection algorithm, we improve the straight-forward method of generating a random permutation until a derangement is obtained. This and our procedure are both linear with respect to the number of calls to the random generator, but we obtain an improvement of more than 36%. By using probability generating functions we perform an exact average analysis of the algorithm, showing that our approach is rather general and can be used to analyze random generation procedures based on the same rejection technique. Moreover, emphasis is given to combinatorial sums and a new interpretation of a known infinite lower triangular array is found.