Graph Traversal - BFS
Graph traversal is technique used for searching a vertex in a graph. The graph traversal is also used to decide the order of vertices to be visit in the search process. A graph traversal finds the egdes to be used in the search process without creating loops that means using graph traversal we visit all verticces of graph without getting into looping path.
There are two graph traversal techniques and they are as follows...
- DFS (Depth First Search)
- BFS (Breadth First Search)
BFS (Breadth First Search)
BFS traversal of a graph, produces a spanning tree as final result. Spanning Tree is a graph without any loops. We use Queue data structure with maximum size of total number of vertices in the graph to implement BFS traversal of a graph.
We use the following steps to implement BFS traversal...
- Step 1 - Define a Queue of size total number of vertices in the graph.
- Step 2 - Select any vertex as starting point for traversal. Visit that vertex and insert it into the Queue.
- Step 3 - Visit all the adjacent vertices of the verex which is at front of the Queue which is not visited and insert them into the Queue.
- Step 4 - When there is no new vertex to be visit from the vertex at front of the Queue then delete that vertex from the Queue.
- Step 5 - Repeat step 3 and 4 until queue becomes empty.
- Step 6 - When queue becomes Empty, then produce final spanning tree by removing unused edges from the graph