I like your code. I understand it better than mine. But you don't save any pointer to the start of the memory allocated for 'r' and 'q', so you could never free this memory.

yes, I was wrong. I'm sorry bro )

long maximum is platform-dependent. On CW it's 8 bytes, and if your solution failed, it's wrong.

you have test case at least with 11 digit number, long maximum is 2^31, long long 2^63 (long's size in C 4 bytes), that is why i got some tests wrong but program was ok

With long long it works correctly

Maybe you should tell why long must be replaced instead of saying "ha-ha something's gonna work"?

Hi! I think you have some issue in input parameters of function in C language.

Now : bool loneliest(long n)

Should be : bool loneliest(long long n)

With long long it works correctly :)

To me this solution (and others alike) are the best. They are the only ones that cover the following case:
"10 shots and 2 beer". Most solutions give 3 (1 + 0 + 2) instead of 12 (10 + 2) as the result.