Calculate the longest path in a directed acyclic graph in terms of node weights (Python)

Use this class to get (one of) the paths with the largest sum of node weights in a directed acyclic graph (DAG). After constructing the empty object, use add_node(label, weight) and add_edge(label1, label2) to build the graph, and then call longest_path to retrieve the path and the sum of the weights. This latter operation is destructive and will delete the graph.

    dag = DAGLongestPath()
    for i in range(6): dag.add_node(i, i)
    dag.add_edge(3, 5)
    dag.add_edge(2, 5)
    dag.add_edge(2, 4)
    dag.add_edge(1, 2)
    print(dag.longest_path())