#### Course Schedule I was using DFS to search through each node in the Graph and using HashMap to store the list of prerequisites. A set was used to store the course that have been scheduled, and to check if there is a loop inside the graph. Time complexity: O(N+P). N is the number od course, and P is the number of prerequisites. #### Network Delay Time I was using BFS to go through each node in the Graph and using HashMap containing MinHeap to store the path, if I found the samller Path I pop it out of the minHeap and return the shortest path store in the global variables. Time complexity: O(NlogV) where N is the number of node in the graph, and V is the number of neighbours of the node in the graph.