Kata

Thanks Donald, it was an issue that I failed to spot, I have taken another look at it and found it.

This kata is timing out on simple sscanf/sprintf solutions which for this rank should be sufficient or are further optimisation needed?

https://docs.codewars.com/languages/c/authoring/memory-management-techniques/#mixed-approach-malloc-in-the-solution-and-free-in-tests

Performing heap memory allocation in the user solution and freeing the memory in tests is an anti-pattern that should be avoided at all costs. Please change the semantics of the user solution to either:

• (Recommended) Receive as an extra argument a (pre-allocated) writable character buffer large enough to hold the result; or
• (Not recommended) Keep the current semantics of the user solution, but require the user to implement their own function to free the allocated memory; however, this (testing proper memory management by the solver) is difficult, if not impossible to test explicitly on Codewars

A recommended function signature:

void network_cidr(const char *ipv4_addr, const char *netmask, char *result);

Alternatively, return the output buffer result as well but this needs to be explicitly tested and documented:

char *network_cidr(const char *ipv4_addr, const char *netmask, char *result);