Degree of each vertex in the graph
Degree(vertex) = The number of edges incident to the vertex(node).
In other words, the number of relations a particular node makes with the other nodes in the graph.
In-degree of a vertex is the number of edges coming to the vertex.
In-degree of vertex 0 = 0
In-degree of vertex 1 = 1
In-degree of vertex 2 = 1
In-degree of vertex 3 = 3
In-degree of vertex 4 = 2
Out-degree of a vertex is the number edges which are coming out from the vertex.
Out-degree of vertex 0 = 3
Out-degree of vertex 1 = 2
Out-degree of vertex 2 = 1
Out-degree of vertex 3 = 1
Out-degree of vertex 4 = 0
A vertex with degree one is called a pendant vertex.
A vertex with degree zero is called an isolated vertex.