To create a directed graph in Python for solving problems on LeetCode, you typically represent the graph using data structures such as adjacency lists.

Well, if I remember my graph theory well enough, if A is the adjacency matrix of the graph, each entry of A^n is the number of ways to get between the corresponding nodes in n steps or less. So ...

Karl Rohe, Tai Qin, Bin Yu, Co-clustering directed graphs to discover asymmetries and directional communities, Proceedings of the National Academy of Sciences of the United States of America, Vol. 113 ...