RunTime Exception. But the description stays: All inputs are positive, non-zero digits.

impressive implementation of permutations(), very concise and speaks for itself ;)

Why you are sure that division is always would be without remainder ?

there some useful images that i use :)

https://gerardnico.com/lang/regexp/regexp

could you please add some explanation to your solution ?

could be here any graphical interpretation of solution ? just can't get how this works

how did you figure out this ? is the solution in some expanded form related to the binary tree?

how did you figure out this ?
just interesting ... :)

could you please attach any explanations\links about how it works ?
just can't get it (

hmm... I thought there's no associative arrays in C

@MistyPhi
so... issue seems to be still open. but you can pass this one even though the issue isn't fixed.

ok, sorry