Question 6
In a directed graph represented by an Adjacency Matrix A, where A[i][j] = 1 indicates an edge from vertex i to vertex j, how is the in-degree of vertex j computed?
An edge from i to j contributes to A[i][j] = 1. Therefore, incoming edges to vertex j correspond to 1s in column j. In-degree of $j = sum of elements$ in column j.