Adjacency List Representation

• Vertices v₀ ... v_{n -1}
• Vector V of lists
• V[i] = the adjacency list for vertex v_i
• List of vertices reachable in one step from vertex v_i
• Lists other end of each edge counted by out(v_i)
• Digraph::AddEdge(x,y) { V[x].PushBack(y); }
• Ungraph::AddEdge(x,y) { V[x].PushBack(y); V[y].PushBack(x); }
• Storage size = Θ(eSize + vSize) = Θ(eSize + n)
• Edge access time = Θ(outDegree(vertex))
• Random access to adjacency list
• Sequential search in the adjacency list
• Amortized edge access time = Θ(1) for sparse graphs