On one side I feel bad for not figure this kind of solutions out just cuz' I forgot certain lang feature exists, on the other side I love checking them out to see how they work.

But hey, practice makes perfect

what a beautiful solution!

Vector: so good, ya gotta include it twice! :)

tysm, this helped alot!

For even more improve performance, change n.second % 2 != 0 to n.second & 1.

If you click in the 'Output' section (next to 'Instructions') you can find the time your code took on the top left hand corner above 'Test Results:'.

Hello. Where can I see the speed of code to compare solutions?

Good solution, but there's no need to use const auto& while iterating on container with builtin types such as int. It doesn't improve performance but affects readability.

This solution is very slow, look at the rock4259 solution, it is an order of magnitude faster. 572 ns and 35 ns respectively.

Thank you!

This type of metaprogramming is definitely more difficult than 4Kyu.