Implement `DoubleEndedIterator` for `Powerset`

rust-itertools / itertools

Extra iterator adaptors, iterator methods, free functions, and macros.

https://docs.rs/itertools/

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Implement `DoubleEndedIterator` for `Powerset` #905

Closed TennyZhuang closed 6 months ago

Philippe-Cholet commented 6 months ago

Duplicate of #620 which contains arguments on why it's not implemented.

TennyZhuang commented 6 months ago

Duplicate of #620 which contains arguments on why it's not implemented.

Ok, I just take a look at the implementation and the explanation seems good to me.

BTW, if we use a bitwise-based implementation, I guess the rev can be implemented in a naive solution?

Philippe-Cholet commented 6 months ago

No matter the implementation or the iterator, support a DoubleEndedIterator implementation can have some cost to store backward informations (and not just forward ones).

But I guess that if you use a bitwise implementation (which is surely lightweight) then the cost would probably be quite small and more acceptable for you than here for us.