I don't see how this could be considered "Best Practice" or "Clever".
It needs O(n*logn) in time to do something that could be done in O(n)

I don't see how this could be considered "Best Practice" or "Clever".
It needs O(n*logn) in time to do something that could be done in O(n)

It's a broken solution!
MCDXLIII is 1443 but your
solution("MCDXLIII") is 1663
because while reducing, (1000+100)>500 while you thought that 100<500

Here C.
3rd test expects 80 but result is 81.