Graph: Initialization & Traversal

[sophryu99]

Initializing graph

graph = {}
        
        for edge in edges:
            graph[edge[0]] = graph.get(edge[0], []) + [edge[1]]
            graph[edge[1]] = graph.get(edge[1], []) + [edge[0]]
            
        print(graph)

[[0,1],[1,2],[2,0]]
{0: [1, 2], 1: [0, 2], 2: [1, 0]}

[sophryu99]

preMap = {i: [] for i in range(numCourses)}

        # map each course to : prereq list
        for crs, pre in prerequisites:
            preMap[crs].append(pre)