dont use strcat() on uninitialized memory (e.g. that returned by malloc())

My bad code, Although A x B == B x A, so I'm not sure that it matters all that much.

Remember to mark as spoiler next time.

Но ведь js поддерживает индексацию с конца.
arr = [3, 2, 3]
arr[-1] === arr[0] // 3 = 3
sometimes it return error or not?

It does, but javascript will return "undefined" for out-of-bounds errors instead of crashing, so it works anyway.

Production code is boring.

You can check out my 2 and 1 Kyu C translations though. I made about 50% of all of them.

Yes, it is a good way to learn new things by studying other user solutions.

fmax and smax have type int. therefore, the expression fmax - smax has type int also.
In general, a signed integer type T cannot handle the difference between T_MAX and T_MIN. (e.g. 2 ** 31 - 1 - -(2 ** 31) == 2 ** 32 - 1 which does not fit in an int (it is equal to UINT_MAX)).

You seem to have understood that since you use diff with type unsigned; but it is too late because when the assignment is performed, the integer overflow has already taken place in the expression. You need to use larger types at the time you compute the difference.

@yar83: Consider we receive an array of int, but we have to return a long, and there's a reason for that ;)

it sounds like you're not handling int overflow properly, but without seeing your code it's hard to tell. if you post your code (with markdown and a spoiler flag) i can help you find the problem

In this case it lowercases the letter.