having the same issue

@epicshaner If you did with JS or TS, you can check mine. I'm learning clean code stuff and did this kata for training so it should be quite easy to understand.

@epicshaner IIUC you can only "View Solution" if you also solved in the same language...

How come there is no solution from you to view? I wanted to know how you got a simple implementation out of this kata.

fails for n = 99999999999999999

duplicate issue

yes

One possible solution is to use correct data structure with precomputed values

If you notice in the description it says "return the NEXT smaller positive integer containing the same digits"
The NEXT smaller integer for '531' is '513' NOT '351'

the EBNF sucks can I use C's grammar for this ? for example
identifier ::= letter | '' { identifier-char }
identifier-char ::= '' | letter | digit

would make '__' a valid variable name

depends on the language

you don't need integer_sequence at all, also, lambdas might be useful for this...

hard as hell if you don't know templates that well, like me