It can only be compiled with a correct flag.
Beginner Hint 1: C++ Features
chal.cppuses various C++ language and library features.- The
constexprkeyword indicates that variables or functions can be calculated at compile time. - The
static_assertkeyword checks if a condition is true, and shows an compile-error message if it does not; inchal.cpp, it is used as a flag checker. - The
templatekeyword allows to abstract of type arguments and non-type arguments for functions and types. - The
std::index_sequencetype represents a sequence ofsize_telements at the type level.std::make_index_sequencecan be used to create a sequence starting from 0 with a specified number of elements. - The
std::integer_sequencetype represents a sequence of elements of a specified type at the type level; inchal.cpp, it is used as a sequence ofstd::uint8_tvalues. - Syntax like
std::size_t... Iorstd::index_sequence<I...>within atemplatefunction represents a feature known as parameter packs. Within the function, syntax such asF(I)...is used to expand the parameter pack. - Syntax like
[](std::size_t i) { return input_string_view[i]; }represents C++ lambda expression; inchal.cpp, it is used as theFtype argument formy_make_sequence_t. - The
decltypekeyword retrieves the type of a value; inchal.cpp, it is used to recover the type from astd::integer_sequencevalue. - The
std::is_same_vvariable indicates whether two type arguments are identical; inchal.cpp, it is used as a flag checker.
- The
- You may want to investigate the details further if necessary.
Beginner Hint 2: Approach to Solving the Challenge
- It is a good idea to start by understanding the calculations performed by the
convolve_ttype, theconvolve_implfunction, and theconvolve_elementfunction. In particular, the relationship between the sequence lengths of the two type argumentsAandBforconvolve_tand the sequence length ofconvolve_titself is crucial. - Let's try examining the elements of the sequence generated by the
odd_random_sequence_ttype; using IDE features might make this easier.