Solution: Count the Number of Edges in an Undirected Graph

To count the number of edges in an undirected graph with n nodes, the approach involves iterating through each vertex and summing the lengths of their adjacency lists. Since each edge is represented twice, the total sum is divided by two to obtain the actual edge count. The time complexity of this method is O(v), where v is the number of vertices, while the space complexity remains O(1) as no additional space is utilized.