P169: Enumeration of all ladder lotteries with $k$ bars

P169: Enumeration of all ladder lotteries with $k$ bars

Input:

A permutation $\pi$ and integer $k$.

Output:

All ladder lotteries of $\pi$ with $k$ bars.

Complexity:

$O(1)$ time per ladder lottery.

Comment:

Ladder lotteries are also known as \textit{Amida kuji} in Japan.

Reference:

[Yamanaka2014] (Bibtex)