Knowee
Questions
Features
Study Tools

Which algorithm efficiently calculates the single source shortest paths in a Directed Acyclic Graph?

Question

Which algorithm efficiently calculates the single source shortest paths in a Directed Acyclic Graph?

🧐 Not the exact question you are looking for?Go ask a question

Solution

The algorithm that efficiently calculates the single source shortest paths in a Directed Acyclic Graph (DAG) is the Topological Sort algorithm. Here are the steps:

  1. Topologically sort the nodes of the graph. This can be done using Depth-First Search (DFS) or Breadth-First Search (BFS). The idea is to visit each node once and only once, and to visit a node before its successors. In a DAG, a topological sort is always possible and results in a linear ordering of the nodes.

  2. Initialize the distance to the source node as 0 and the distance to all other nodes as infinity. This is because we don't know the shortest path to any node yet, except for the source node (the shortest path from a node to itself is always 0).

  3. For each node in the topologically sorted order, relax all of its adjacent nodes. To "relax" an edge means to update the shortest path to the destination node of that edge if a shorter path has been found. This is done by comparing the current known distance to the destination node with the distance to the source node plus the weight of the edge. If the latter is smaller, then we have found a shorter path and we update the distance.

  4. After all nodes have been processed, the shortest path to each node from the source node has been found.

This algorithm works efficiently on DAGs because the topological order allows us to process each edge once and only once, and when we process an edge, we have already processed all edges leading to the source node of that edge. This ensures that we find the shortest path to each node. The time complexity of this algorithm is O(V+E), where V is the number of nodes and E is the number of edges in the graph.

This problem has been solved

Similar Questions

Which algorithm efficiently calculates the single source shortest paths in a Directed Acyclic Graph? ans. topological sort binary search radix sort hash tab

Which graph theory algorithm is used to find the shortest path from a source vertex to all other vertices in a graph?A. Kruskal's algorithmB. Prim's algorithmC. Dijkstra's algorithmD. Floyd-Warshall algorithm

Write an algorithm to find single source shortest path for a graph G whose edge weights arepositive

Which algorithm is used to find the shortest path in a graph?Question 16Select one:Bellman-Ford algorithmTopological SortFloyd-Warshall algorithmDijkstra's Algorithm

Describe, in plain English, an algorithm that given a weighted, directed, acyclic graph G=(V,E,w) (with integer weights) and a vertex s in V calculates the length of the longest path from s to every other vertex v (if a vertex is unreachable from s, then the length of the longest path for that vertex should be infinity). Your algorithm should run in O( |V| + |E| ) time in total, assuming that G is implemented with an adjacency list, as usual. Explain why your algorithm has this running time.[Hint: you might want to consider a new graph G', more or less similar to G, and reduce the problem for G to a problem for G' that we have solved in the lectures]

1/3

Upgrade your grade with Knowee

Get personalized homework help. Review tough concepts in more detail, or go deeper into your topic by exploring other relevant questions.