# Blog

## What is depth first spanning tree? ## Is depth first search optimal?

Completeness: DFS is complete if the search tree is finite, meaning for a given finite search tree, DFS will come up with a solution if it exists. Optimality: DFS is not optimal, meaning the number of steps in reaching the solution, or the cost spent in reaching it is high.Aug 20, 2021

## Does BFS give a spanning tree?

3 Answers. If your graph is unweighted, or equivalently, all edges have the same weight, then any spanning tree is a minimum spanning tree. As you observed, you can use a BFS (or even DFS) to find such a tree in time linear in the number of edges.

## What is depth first search with example?

Depth-first search (DFS) is an algorithm for traversing or searching tree or graph data structures. The algorithm starts at the root node (selecting some arbitrary node as the root node in the case of a graph) and explores as far as possible along each branch before backtracking.

## Is depth first search Greedy?

No. "Best first" simply means that it relies entirely on some heuristic that scores possible options, and expands the best options first. Depth first search uses no such heuristic.Mar 1, 2012  ### Which is better BFS or DFS?

BFS is better when target is closer to Source. DFS is better when target is far from source. As BFS considers all neighbour so it is not suitable for decision tree used in puzzle games. DFS is more suitable for decision tree.Nov 26, 2019

### What is depth-first search and how does it work?

Depth-first search (DFS) is an algorithm for searching a graph or tree data structure. The algorithm starts at the root (top) node of a tree and goes as far as it can down a given branch (path), then backtracks until it finds an unexplored path, and then explores it.

### How do you fix depth-first search?

The basic idea is as follows: Pick a starting node and push all its adjacent nodes into a stack. Pop a node from stack to select the next node to visit and push all its adjacent nodes into a stack. Repeat this process until the stack is empty.

### What is greedy best first search?

Greedy best-first search algorithm always selects the path which appears best at that moment. It is the combination of depth-first search and breadth-first search algorithms. It uses the heuristic function and search. Best-first search allows us to take the advantages of both algorithms.

### Why is BFS not optimal?

As far as the optimality of the solution is concerned, the BFS algorithm stops at the shallowest goal found. The shallowest goal node need not compulsorily be the optimal goal node. ... When searching a state space for a path to a goal state then DFS may produce a much longer path than BFS.Jul 10, 2019

### Why do we use DFS?

Using DFS we can find path between two given vertices u and v. We can perform topological sorting is used to scheduling jobs from given dependencies among jobs. ... Using DFS, we can find strongly connected components of a graph. If there is a path from each vertex to every other vertex, that is strongly connected.Aug 27, 2019

### Is Depth First Search FIFO?

The depth-first search uses a Stack to remember where it should go when it reaches a dead end. Stack (Last In First Out, LIFO). For DFS, we retrieve it from root to the farthest node as much as possible, this is the same idea as LIFO. Queue (First In First Out, FIFO).Oct 14, 2010

### What will be the result of depth first transversal in the following tree?

What will be the result of depth first traversal in the following tree? Explanation: Depth first search is similar to pre order traversal in a tree. So here we will get the same result as for the pre order traversal (root,left right).

### Why is it impossible to have BFS forward edges?

There are no forward edges. For a forward edge u , v to exist, u , v must not be in the BFS tree and u is an ancestor of v in the BFS tree. Thus, d [ u ] + 1 < d [ v ] must hold. That is, there must be at least one vertex in the predecessor path from v to u .

### What is spanning tree and why use spanning tree?

• Spanning tree protocol (STP) is a Layer 2 network protocol used to prevent looping within a network topology. STP was created to avoid the problems that arise when computers compete for the ability to use the shared telecommunications path on a local area network (LAN).

### What is depth first?

• Depth-first search is a systematic way to find all the vertices reachable from a source vertex, s. Historically, depth-first was first stated formally hundreds of years ago as a method for traversing mazes.

### What is depth first search?

• Depth First Search. The basic idea is as follows: Pick a starting node and push all its adjacent nodes into a stack. Pop a node from stack to select the next node to visit and push all its adjacent nodes into a stack. Repeat this process until the stack is empty. However, ensure that the nodes that are visited are marked.

### What is depth first search algorithm?

• Depth-first search (DFS) is an algorithm for traversing or searching tree or graph data structures. The algorithm starts at the root node (selecting some arbitrary node as the root node in the case of a graph) and explores as far as possible along each branch before backtracking.