I was recently trying to solve this problem: https://codeforces.com/problemset/problem/1210/C. After realizing it was finding the sum of gcd on paths, I thought that this problem was a direct application of Centroid Decomposition.
However, my submission (https://codeforces.com/contest/1210/submission/61229151) got WA on test case 6. I do not think my code is the problem as I have verified it with this problem: http://www.usaco.org/index.php?page=viewproblem2&cpid=286
I am wondering if my logic of choosing to use centroid decomposition is wrong. Any help would be greatly appreciated!