Personally I hope LeetCode could support functional programming languages like OCaml, Haskell, LISP, and etc. (It's great it supports Scala, but just not enough :-) )

This is beneficial to both the platform and users as the platform will attract more FP programmers and the users will have more options to go.

Other websites like HackerRank and CodeWars have already done this, hurry up LeetCode!