P387: Enumeration of all binary string with fixed number ones

P387: Enumeration of all binary string with fixed number ones

Input:

Two integers $n$ and $k$, where $n \ge k$.

Output:

All binary string with length $n$ and $k$ ones.

Complexity:

$O(1)$ time per binary string.

Comment:

Reference:

[Bitner1976] (Bibtex)