Message (IOI24_message) is a problem/puzzle from IOI (International Olympiad in Informatics) which even though I looked at the others solution, I still can't understand how it works.
Statements of the problem: https://oj.uz/problem/view/IOI24_message
What I think may be the way to do it
If anybody understands the solution to this problem, please comment under this post, Thanks in advance!