permutations_iter

An iterative permutation generator without recursion for Rust.

Iterator Permutations::of(n) generates permutations of 0..n iteratively using Steinhaus-Johnson-Trotter algorithm with Even's modification.

Each next() call has $O(n)$ time and space complexity.

Not optimized. At all. Any improvements are welcome.

Published under MIT license.

lib.rs:

Generate permutations iteratively without recursion.

Permutations.of(n) function generates an iterator instance for permutations of 0..n.

Permutations.next() uses Steinhaus-Johnson-Trotter algorithm with Even's modification to generate the next permutation in $O(n)$ time.

Each iterator is one-way. You need to construct a new one for iterating again.