LINK TO THE PROBLEM ( http://codeforces.com/contest/216/problem/B )

I am not getting the logic …I also tried to learn form others code but …again m not getting their logic .here is the the link of a solution( http://codeforces.com/contest/216/submission/16612019 ) but i am not able to understand why the root() function is designed like this and how it works…

# A PROBLEM ON GRAPH-THEORY

**popo_popo333**#1

**ayushagg31**#2

Read this complete article and I am sure You will get the idea of Root() function.

I will solve this question after some time, then I will suggest you the approach.But I recommend you to read this article first.This will surely help you to solve many others problems too.

**ayushagg31**#3

I guess you have to print number of close loop in given graph,where number of students are node and given pair are edges.

**ayushagg31**#4

So basically root() function here tells you about close loop formed in given graph.This is concept is basically used in Kruskal algo to do the check for closed loop.