I am trying to solve this problems Problem.I think the solution is to find the number of connected components for the given graph.

So by doing a simple DFS we can get the no of connected components.

Am I right or not ?

No, As the question states that **b** will get light up if **a** does which means that graph is **directed**.

so if u are talking about * strongly connected components* in directed graph, it will not help you

because in the input 2 you will observe that no of SCC is 4.