Review: Adjacency List
l Adjacency list: for each vertex v V, store a
list of vertices adjacent to v
l Example:
n Adj[1] = {2,3}
n Adj[2] = {3}
n Adj[3] = {}
n Adj[4] = {3}
l Storage: O(V+E)
n Good for large, sparse graphs (e.g., planar maps)