Couple of days ago I got to know that Radewoosh is on Atcoder with username 'stonefeang'. So I was wondering whether this username has been taken by someone on codeforces or not. But to my surprise when I type 'stonefeang' in the profile url or in search handle option it takes me to Radewoosh's profile.

How does it happen?

I was learning rabin karp algorithm and solving a basic problem of finding indices of pattern in a string with the help of string hashing technique. But the code is just not printing out anything.

I used this algorithm yesterday to solve a problem and got AC but now I'm unable to find where's the issue.

here's my Code Please help.

Here's a Problem from Atcoder beginner contest 154, I'm unable to understand the problem completely, I mean what they are asking and also the editorial, can someone explain the solution?

Problem-D this is D problem of Atcoder beginner contest 163 from last night. I'm still unable to get the logic, can anyone explain the solution?

How can I get the path between two nodes if I've used LCA algorithm? What is the fastest way to get the smallest path between those nodes?