The last contest of CodeChef (this one) had 2 rerooting problems and it wasn't really solved by many people(even in Div1), so I figured it's something not many people know.

So I have made a tutorial video on the same: https://www.youtube.com/watch?v=7_huTWwl5jM&ab_channel=CMC

In it I discuss:

• How to identify which problem requires this

• How to go about solving it

• How to implement without much hassle

• Some problems that require it and their solution/hint

When I first came up with this rerooting my implementation was pretty terrible but now it's much better IMO, so I also wanted to share it.