Recently, I was trying to solve this problem : https://community.topcoder.com/stat?c=problem_statement&pm=10469&rd=13749&rm=&cr=22697731.
Please note, this problem doesn't have an editorial. ( It's magically still coming soon even though it's from 2009).
I was constructing a functional graph G where an edge from node i to node j, means that the ith index contains the jth value.
Then, The graph must all of it lie in one cycle ( one SCC ) for the conditions to hold. Otherwise answer ( number of swaps ) is #SSC's — 1. Each component must be linked to another and only one.
The problem however lies in constructing the permutation. I was following an approach that involves greedily merging components starting from the first component that contains zero, but I keep getting WA on a large case.
Any help would be appreciated.