I can see a few potential problems here:

0. Since you allocated a char* array of input.size() elements, result[input.size()] is out of bounds.
1. Similarly, std::string's size() is the number of characters - it doesn't include the trailing \0 needed for C-style strings. So every strcpy here risks doing a buffer overflow (risks, because it is possible for C++ std::strings to contain a null in the middle, terminating the strcpy mid way).
2. You have set a limit on the number of elements of strings you delete, but then delete strings irrespective of whether that limit was breached. This risks a memory leak if the limit was exceeded.

I can see a few potential problems here:

0. Since you allocated a char* array of input.size() elements, result[input.size()] is out of bounds.
1. Similarly, std::string's size() is the number of characters - it doesn't include the trailing \0 needed for C-style strings. So every strcpy here risks doing a buffer overflow (risks, because it is possible for C++ std::strings to contain a null in the middle, terminating the strcpy mid way).
2. You have set a limit on the number of elements of strings you delete, but then delete strings irrespective of whether that limit was breached. This risks a memory leak if the limit was exceeded.
3. You use the array version of new new <type>[<size>]; This means you need to use the array version of delete delete [] <object> (Note the square brackets).