Here is my solution to SPOJ Problem CHAIN : https://ideone.com/Egu19B

My solution involves maintaining 3 arrays, for containing the root node of each disjoint set as well as the root nodes of predator and prey of that disjoint set. The solution gives a WA, I've verified it for a lot of test cases and am unable to understand why it fails. Can anybody tell me where my solution fails, perhaps even provide me with a test case where it does not work?

The problem : http://www.spoj.com/problems/CHAIN/

Thanks!