Link to problem: http://codeforces.com/problemset/problem/505/D
My submission: http://codeforces.com/contest/505/submission/18861557
My idea is to count the amount of sub-trees of the graph that doesn't contain a cycle, and the answer would be n-(amount of sub-trees without a cycle). However my code fails on the test case 6 and I have no idea how did the test case got me... Can anyone point out the flaw of my code or even my approach on solving this problem?
Here is test 16 that fails your program. Also, graph can't be called a tree if it has cycle.
Thanks for the test case, now I see the flaw my logic, didn't thought through the whole merge algorithm. :D
Also for pointing out the wrong tag, now it has been updated.