Star Graph - Method 1

A star graph has one center vertex connected to all other vertices. The center has degree $n-1$, and all other vertices have degree $1$.

You could build an adjacency list and count degrees for each vertex. Check if one vertex has degree $n-1$ and all others have degree $1$. This works but requires storing the graph.

There is a smarter approach using edge counting. I'll show you the trick in the next unit.