Two Reflected Gray Code-Based Orders on Some Restricted Growth Sequences
We consider two order relations: that induced by the m-ary reflected Gray code and a suffix partitioned variation of it. We show that both of them when applied to some sets of restricted growth sequences still yield Gray codes. These sets of sequences are: subexcedant and ascent sequences, restricte...
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Veröffentlicht in: | Computer journal 2015-05, Vol.58 (5), p.1099-1111 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | We consider two order relations: that induced by the m-ary reflected Gray code and a suffix partitioned variation of it. We show that both of them when applied to some sets of restricted growth sequences still yield Gray codes. These sets of sequences are: subexcedant and ascent sequences, restricted growth functions and staircase words. In particular, we give the first suffix partitioned Gray codes for restricted growth functions and ascent sequences; these latter sequences code various combinatorial classes as interval orders, upper triangular matrices without zero rows and zero columns whose non-negative integer entries sum up to n, and certain pattern-avoiding permutations. For each Gray code, we give efficient exhaustive generating algorithms and compare the obtained results. |
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ISSN: | 0010-4620 1460-2067 |
DOI: | 10.1093/comjnl/bxu018 |