Breadth-first search, Data Structure & Algorithms

Assignment Help:

Breadth-first search starts at a given vertex h, which is at level 0. In the first stage, we go to
all the vertices that are at the distance of one edge away. When we go there, we marked
as "visited," the vertices adjacent to the start vertex s - these vertices are placed into level 1.
In the second stage, we go to all the new vertices we can reach at the distance of two edges
away from the source vertex h. These new vertices, which are adjacent to level 1 vertex and not
previously assigned to a level, are placed into level 2. The BFS traversal ends when each vertex
has been finished.

The BFS(G, a) algorithm creates a breadth-first search tree with the source vertex, s, as its root.
The predecessor or parent of any other vertex in the tree is the vertex from which it was first
developed. For every vertex, v, the parent of v is marked in the variable π[v]. Another variable,
d[v], calculated by BFS has the number of tree edges on the way from s tov. The breadth-first
search needs a FIFO queue, Q, to store red vertices.

Algorithm: Breadth-First Search Traversal

BFS(V, E, a)

1.
2.             do color[u] ← BLACK
3.                 d[u] ← infinity
4.                 π[u] ← NIL
5.         color[s] ← RED                 ? Source vertex find
6.         d[a] ← 0                               ? Start
7.         π[a] ← NIL                           ? Stat
8.         Q ← {}                                ? Empty queue Q
9.         ENQUEUE(Q, a)
10        while Q is non-empty
11.             do u ← DEQUEUE(Q)                   ? That is, u = head[Q]
12.
13.                         do if color[v] ← BLACK    ? if color is black you've never seen it before
14.                                 then  color[v] ← RED
15.                                          d[v] ← d[u] + 1
16.                                          π[v] ← u
17.                                          ENQUEUE(Q, v)
18.                 DEQUEUE(Q)
19.         color[u] ← BLACK

 

 


Related Discussions:- Breadth-first search

Doubly linked lists-implementation, In any singly linked list, each of the ...

In any singly linked list, each of the elements contains a pointer to the next element. We have illustrated this before. In single linked list, traversing is probable only in one d

Insertion sort, Data array A has data series from 1,000,000 to 1 with step ...

Data array A has data series from 1,000,000 to 1 with step size 1, which is in perfect decreasing order. Data array B has data series from 1 to 1,000,000, which is in random order.

Explain almost complete binary tree, Almost Complete Binary Tree :-A binary...

Almost Complete Binary Tree :-A binary tree of depth d is an almost whole binary tree if: 1.Any node and at level less than d-1 has two children. 2. for any node and in the tree wi

Program on radix sort., Write a program that uses the radix sort to sort 10...

Write a program that uses the radix sort to sort 1000 random digits. Print the data before and after the sort. Each sort bucket should be a linked list. At the end of the sort, the

frequenty count of function, Ask question find frequency count of function...

Ask question find frequency count of function- {for(i=1;i {for(j=1;j {for(k=1;k } } }

Draw trace table and determine output of number, Draw trace table and deter...

Draw trace table and determine output from the following flowchart using following data: Number = 45, -2, 20.5

Stack, how we will make projects on stack in c?

how we will make projects on stack in c?

Algorithm for inorder traversals, Step-1: For the current node, verify whet...

Step-1: For the current node, verify whether it contain a left child. If it has, then go to step-2 or else go to step-3 Step-2: Repeat step-1 for left child Step-3: Visit (th

Hash function, Q. Define the graph, adjacency matrix, adjacency list, hash ...

Q. Define the graph, adjacency matrix, adjacency list, hash function, adjacency matrix, sparse matrix, reachability matrix.

State about the simple types - built-in types, State about the Simple types...

State about the Simple types - Built-In Types Values of the carrier set are atomic, that is, they can't be divided into parts. Common illustrations of simple types are inte

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd