Number of Vertices = 4
Number of Edges = 0

The graph is
Number of Vertices = 4
Number of Edges = 4
4  2  3  
1  4  
1  
1  2  


The graph after deleting (2,1) is
Number of Vertices = 4
Number of Edges = 3
4  3  
4  
1  
1  2  

existsEdge(3,1) = 1
existsEdge(1,3) = 1
inDegree(3) = 1
outDegree(1) = 2
Number of Vertices = 4
Number of Edges = 3

Vertices adjacenct to vertex 4
1
2