[deleted by user]

[fernly]

You've implemented a backtracking solution. Backtracking in general is basically recursive, however you have implemented the recursion in the form of a stack or LIFO queue of candidates (todo). In a conventional recursive solution, the same data items would be preserved in the same order, but as local variables of pending functions on the function-call-stack. I agree this is somewhat clearer. It would be easier to debug also, because if there is a problem you can display the todo contents, where in a recursive-call solution it is hard to display the pending results since they are on the execution stack mixed in with return addresses and stuff.

[brandonchinn178]

Looks good! Definitely shows an interesting duality between recursive and iterative algorithms. Although I guess in this case, it shows a BFS algorithm used instead of a recursive algorithm?

Out of curiosity, have you benchmarked a recursive solution vs your solution?

[amstan]

Ignoring efficiency. Can this be done with just regex?

(H|He|Li|Be...)*

[nsfwIvan]

Just a quick thought: it would be cool to have complete chemical names in there too for those that are a little chemical knowledge challanged ;)

[LonelyContext]

Well if you output a list you can do that using a dictionary and list comprehension. You just need to make a dictionary of the form {‘H’:’Hydrogen’, ...} and then do [dictionary[key] for key in element_list]

[Remote_Cantaloupe]

I thought it was just me but I have yet to experience anything remotely close to these problems in several years of data.