How to solve CHGORAM in August19 challenge?

[ssjgz]

There are @vijju123’s Setter’s Notes here:

Invitation to CodeChef August Long Challenge 2019

Hi all, Unfortunately, due to some personal reasons the editorials of following problems are delayed. They will be posted by end of this week tenatively KS1 - Done SYNBAC - Pending Approval CHGORAM CSTREE TSEQ

and also my fully-documented solution with high-level overview and lots of comments :

https://www.codechef.com/viewsolution/25925347