1. DiGraph Definitions Adjacency Matrix Adjacency List
Directed Graphs
DiGraph Definitions
Adjacency Matrix
Adjacency List
4/15/2019
CS 303 – Directed Graphs
Lecture 19

2. Directed Graphs (DiGraph)
G = (V, E)
V = {v} vertices/nodes/points
E = {e} (directed) edges/arcs/lines
Labels
Arcs/vertices may have an associated label
Arc
ordered pair of Vertices - (v,w) – vw
From v To w
w Adjacent To v v w
tail
head
4/15/2019
CS 303 – Directed Graphs
Lecture 19

3. Graph Definitions Path v1, v2, ..., vn v1  v2, v2  v3, ... vn-1  vn
From v1
Passes through v2, ..., vn-1
Ends at vn
Length = n-1 (count the arcs, not the vertices)
Simple Path
all vi (except perhaps v1 and vn) are DISTINCT
Cycle
(v1, ..., vn) – Length >= 1 1 2 3 4
3243 = cycle
4/15/2019
CS 303 – Directed Graphs
Lecture 19

4. Graph Operations T/F  (i  j) in E? (i.e., MEMBER((i,j),E))
{v}  Adjacent(i)
Quicky Implementation – any implementation of SET
4/15/2019
CS 303 – Directed Graphs
Lecture 19

5. Adjacency Matrix Representation
4/15/2019
CS 303 – Directed Graphs
Lecture 19