I respectfully disagree.

i added plenty of details in the initial code; it is more than enough. if you dont know what an array or a comparison function are it is not the kata's responsibility to teach you that. also, low level languages are obviously harder than higher level languages; so complaining about the kyu rank is pointless.

in the initial code:

// array elements have type const char *

Doing the C version.

What excactly is passed on to the testfunction? Pointers to strings? Pointers to arrays of strings? Pointers to pointers? Does it say so anywhere?

Based on the description of the task I would expect to get two pointers to strings, and return -1, 0 and 1 depending on which string should be first. But I don't get that.

This is a kyu 7. Specific instructions expected.

I was expecting the supplied data not to be mutable. But as I wrote I'm not sure how it was intended.

I am not sure I understand the issue, and when I am trying to sort the input array I get an expected warning:

solution.c:13:9: warning: passing 'const unsigned int *' to parameter of type 'void *' discards qualifiers [-Wincompatible-pointer-types-discards-qualifiers]
  qsort(gifts, length, sizeof(unsigned), cmpfun);

What would be the behavior expected by you? Do you mean that it should be generally not allowed to mutate inputs in this kata?

What do you mean? Multiplication is modular, the same way as addition and subtraction are. Signedness of multiplication only changes the high part due to different extension of the most significant bit to the high part.

I'll just point out that imul can't correctly multiply uint64_t. Not that I believe really larges values has been used here.

I think it's better to make input and output unsigned.

Already reported below.

The description has been updated and unified, you need to publish a new fork. Merge conflicts in the future should be limited thanks to unification.

fixed

Thanks!