Hi. Don't approve it yet however, I haven't solved the bug yet. Don't worry about that, I'll approve the fork myself when I think I solve it (I am able to do it as a mender).

Strongly changing the difficulty after the rank of the kata has already been assigned is not the best solution.

approved some time ago :)

Is it solvable right now in C++;?

NB: It is better to reverse exp rather than chain.
exp is a range and slicing a range generates a new range in constant time,
whereas in order to reverse chain list, you need to read the whole array.

Approved at average assessed rank of kyu 6.

I unflagged the spoiler, the world may read this message :)

Hi @raulbc777 : fixed the bug in C++ (I guess) => didn't check the random or review the entire code. I let you do that.

BTW... the C++ prototype (uint64_t, etc...) is 120% weird !!!

Thanks for keep posting great kata's!

Indeed seems to have an error in C++: my solutions passes the TEST fine, but have a compilation error when "attempting" =>

./tests.cpp:22:40: error: use of undeclared identifier 'h'
    for (; lowest < 10; lowest++) r += h(n - lowest, digits - 1, lowest);
                                       ^
1 error generated.

"claryfy" -> "clarify"

Typo Touring -> Turing (Unless you are quoting a different Alan)

It's using your test generation closely. The only thing I changed was the number of tests and how t was generated since I was getting a lot of results expecting 0. Either way I believe it's fine, but totally your call.