Efficient generating algorithm for permutations with a fixed number of excedances
نویسنده
چکیده
In this paper, we develop a constant amortized time (CAT) algorithm for generating permutations with a fixed number of excedances. We obtain a Gray code for permutations having one excedance. We also give a bijection between the set of n-length permutations with exactly one excedance and the set Sn(321, 2413, 3412, 21534)\{123 . . . (n− 1)n}. This induces a Gray code for the set Sn(321, 2413, 3412, 21534)\{123 . . . (n− 1)n}. keywords : Eulerian numbers, permutation, excedance, descent, pattern avoiding permutation, Gray code, generating algorithm.
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