directed-acyclic-graphs

I want to represent a DAG as JSON text and wondering if anyone has tried this and any issues they dealt with in regards to validating if the JSON is actually a DAG. Label each node and make an edge list. That is, for each node store the nodes that it has edges to, for example: { "a": [ "b", "c", "d" ], "b": [ "d" ], "c": [ "d" ], "d": [ ] } You can store many kinds of graphs this way, not just DAGs, so you will need to post-process it to make sure that it has no loops. Just pick a node, DFS, if you see any node more than once it is not a DAG. Then remove all of the nodes you just saw and

I am referring to Skienna's Book on Algorithms. The problem of testing whether a graph G contains a Hamiltonian path is NP-hard , where a Hamiltonian path P is a path that visits each vertex exactly once. There does not have to be an edge in G from the ending vertex to the starting vertex of P , unlike in the Hamiltonian cycle problem. Given a directed acyclic graph G ( DAG ), give an O(n + m) time algorithm to test whether or not it contains a Hamiltonian path. My approach, I am planning to use DFS and Topological sorting . But I didn't know how to connect the two concepts in solving the

I have already seen this and this questions on SO and made the changes accordingly. However, my dependent DAG still gets stuck in poking state. Below is my master DAG: from airflow import DAG from airflow.operators.jdbc_operator import JdbcOperator from datetime import datetime from airflow.operators.bash_operator import BashOperator today = datetime.today() default_args = { 'depends_on_past': False, 'retries': 0, 'start_date': datetime(today.year, today.month, today.day), 'schedule_interval': '@once' } dag = DAG('call-procedure-and-bash', default_args=default_args) call_procedure =

Topological sort can be done using both a DFS(having edges reversed) and also using a queue . A BFS can also be done using a queue . Is there any relationship between the way elements are stored and retrieved while using queue for a BFS to that when used a queue for topological sorting . Clarification will be helpful . Thanks. No, there is not necessarily any relationship. I assume you are referring to the algorithm by Kahn from wikipedia/Topological_sorting#Algorithms , which wikipedia notes: Note that, reflecting the non-uniqueness of the resulting sort, the structure S can be simply a set

Possible Duplicate: [python]: path between two nodes Can anyone point me to some resources on how to do this? I'm using networkx as my python library. Thanks! Omnifarious This is based on Alex Martelli's answer, but it should work. It depends on the expression source_node.children yielding an iterable that will iterate over all the children of source_node . It also relies on there being a working way for the == operator to compare two nodes to see if they are the same. Using is may be a better choice. Apparently, in the library you're using, the syntax for getting an iterable over all the

I'm trying to implement algoritm to convert Directed Acyclic Graph to Tree (for fun, learining, kata, name it). So I come up with the data structure Node: /// <summary> /// Represeting a node in DAG or Tree /// </summary> /// <typeparam name="T">Value of the node</typeparam> public class Node<T> { /// <summary> /// creats a node with no child nodes /// </summary> /// <param name="value">Value of the node</param> public Node(T value) { Value = value; ChildNodes = new List<Node<T>>(); } /// <summary> /// Creates a node with given value and copy the collection of child nodes /// </summary> ///