P385: Enumeration of all topological sortings of a given set in lexicographically

P385: Enumeration of all topological sortings of a given set in lexicographically

Input:

An $n$-element set $S$.

Output:

All topological sortings of $S$ in lexicographically.

Complexity:

$O(m)$ time per solution(?).

Comment:

Reference:

[Knuth1979] (Bibtex)