Yu! Every day I learn something new

use char_indices

it's very legible (the most), but repeating. voted like clever.

You had fallen of the heaven! thank you

wonderful!!

I like that you show any knowledge about character order

oh my God!

of course! it needs an additional bracket pair!

oh, alnum! I hear about it

great!

then, improve the tests, please

The last number of the example he gave is the position, and then find the corresponding number according to the position, and find the sum of the ten hundred thousand digits of this number

Thank you for the Go translation!

I don't understand. Explain me the first test case, please.