Yesterday 's contest had some very good problems , unfortunately, it became unrated.
Problem Link : https://codeforces.com/contest/1573/problem/C
The problem is based on standard topological sort Prerequisite problem .
If the cycle was found in the graph I printed -1 as the answer.
else I found the topical sort of all the chapters , using cycle detection + DFS + queue.
After finding the topological ordering of chapters (stored in a queue a ->b->c->d.... )how do I count the number of times I will have to read the book/number of passes required ???
Please help !!!