PrivacyScanData/visualize/Visualization-of-popular-algorithms-in-Python/BFS

Visualisation of BFS traversal using networkx library

INPUT

Input is taken from the file

input.txt

Sample input

4
0 5 10 5
0 0 5 0
0 10 0 0
0 0 10 0
0

First line contains the number of nodes,say n.(Nodes are numbered as 0,1,2,...(n-1) ) Followed by n*n weighted matrix. Disconnected egdes are represented by negative weight. Last line contains the source node.(i.e, the node from which the BFS should begin)

Draw Graph

Graph is first drawn from the weighted matrix input from the user with weights shown. Edges are marked with black. visualization of the input graph-

BFS traversal

Iterative BFS is performed, using a queue. Each time an edge is encountered, it is marked with red on the graph through the line -

nx.draw_networkx_edges(G,pos,edgelist=[(curr_node,i)],width=2.5,alpha=0.6,edge_color='r')

Visualization of the result-

Complexity

Time: 0(m+n)
where m - number of edges
n - number of nodes