## What is the problem with Dijkstra algorithm?

One of the problems with using Dijkstra’s algorithm on the Internet is that you must have a complete representation of the graph in order for the algorithm to run. The implication of this is that every router has a complete map of all the routers in the Internet.

## What is the problem with Dijkstra algorithm to find single-source shortest path?

Dijkstra’s algorithm solves the single-source shortest-paths problem on a directed weighted graph G = (V, E), where all the edges are non-negative (i.e., w(u, v) ≥ 0 for each edge (u, v) Є E). In the following algorithm, we will use one function Extract-Min(), which extracts the node with the smallest key.

What is the pseudo code not to compute the shortest path in Dijkstra’s algorithm?

5. What is the pseudo code to compute the shortest path in Dijkstra’s algorithm? Explanation: If the known value of the adjacent vertex(w) is not set then check whether the sum of distance from source vertex(v) and cost to travel from source to adjacent vertex is less than the existing distance of the adjacent node.

Does Dijkstra’s algorithm find the shortest path?

Dijkstra’s Algorithm finds the shortest path between a given node (which is called the “source node”) and all other nodes in a graph. This algorithm uses the weights of the edges to find the path that minimizes the total distance (weight) between the source node and all other nodes.

### Is it possible that the Dijkstra algorithm returns a shortest path with a cycle with a weight zero?

Dijkstra itself has no problem with 0 weight, per definition of the algorithm. It only gets problematic with negative weights. Since in every round Dijkstra will settle a node. If you later find a negative weighted edge, this could lead to a shorter path to that settled node.

### Why is it not possible to find a shortest path using Dijkstra’s algorithm having negative edge weights explain with an example?

Then, update the distance from source node A to B with the weight of the edge that connects it with A which is 5 (because 5 < infinity). As 3 is less than 5, but Dijkstra’s algorithm gives the incorrect answer as 5, which is not the shortest distance. Therefore Dijkstra’s Algorithm fails for negative cases.

What is shortest route problem?

The shortest route problem is to find the shortest distance between an origin and various destination points . The shipping company manager wants to determine the best routes (in terms of the minimum travel time) for the trucks to take to reach their destinations.

Why is Dijkstra’s shortest path algorithm considered as greedy?

Dijkstra’s Algorithm maintains a set S of vertices whose final shortest – path weights from the source s have already been determined. Because it always chooses the “lightest” or “closest” vertex in V – S to insert into set S, it is called as the greedy strategy.

#### What is a shortest path model what type of problem can be solved using this type of model?

The shortest path problem is about finding a path between vertices in a graph such that the total sum of the edges weights is minimum. This problem could be solved easily using (BFS) if all edge weights were ( ), but here weights can take any value.

#### Why do we need non negative edges for Dijkstra’s algorithm what goes wrong if we have negative edges?

Since Dijkstra’s goal is to find the optimal path (not just any path), it, by definition, cannot work with negative weights, since it cannot find the optimal path. Dijkstra will actually not loop, since it keeps a list of nodes that it has visited.

How does Dijkstra’s algorithm find the shortest path?

Dijkstra’s Algorithm finds the shortest path between a given node (which is called the “source node”) and all other nodes in a graph. This algorithm uses the weights of the edges to find the path that minimizes the total distance (weight) between the source node and all other nodes.

How is the pseudocode of Djikstra’s algorithm used?

Djikstra’s algorithm pseudocode We need to maintain the path distance of every vertex. We can store that in an array of size v, where v is the number of vertices. We also want to be able to get the shortest path, not only know the length of the shortest path.

## How to speed up Dijkstra’s algorithm using priority queue?

Dijkstra’s algorithm can be easily sped up using a priority queue, pushing in all unvisited vertices during step 4 and popping the top in step 5 to yield the new current vertex. C++ code for Dijkstra’s algorithm using priority queue: Time complexity O (E+V log V):

## How to find the shortest path in a graph?

Particularly, you can find the shortest path from a node (called the “source node”) to all other nodes in the graph, producing a shortest-path tree. This algorithm is used in GPS devices to find the shortest path between the current location and the destination.