Given a tree of n vertices (n <= 1e5) in which the edge is arbitrarily oriented. Also given q queries (q <= 1e5) in which a, b are entered. The problem is quickly answer whether there is a path from a to b.

Thank a lot for your help.

Is there any group on Codeforce where there would be a contest for basic tasks on bit operations?

what different between make_pair() and {}

Why don't text editors have a music player feature? it's also very convenient, you can listen to music while writing code without the need for third-party software.

when I get my rating from last div 2 round I can't wait anymore help me probably u know