StaircaseSizeOfCode on Permutation
The largest k with a subsequence of the Lehmer code whose j-th entry from the right is at least j.
Scanning the code from the right and taking each entry that exceeds the count so far is optimal.
Called as CombinatorialStat(x, "StaircaseSizeOfCode"). The head's page has its examples.
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FindStat St000662
The staircase size of the code of a permutation.
| Object | Value |
|---|---|
[] | 0 |
[1] | 0 |
[1,2] | 0 |
[2,1] | 1 |
[1,2,3] | 0 |
[1,3,2] | 1 |
[2,1,3] | 1 |
[2,3,1] | 1 |
Data from FindStat, the combinatorial statistic finder; the page at findstat.org/St000662 has the rest.