Graph – Find Number of non reachable vertices from a given vertex

Objective: Given undirected graph write an algorithm to count the number of non reachable vertices from a given vertex

Example:

Approach:

Use DFS

• Do the DFS (Depth-First Search) from the given vertex A, Recursively do the DFS from all the adjacent vertices of given vertex A.
• Use the visited array to keep track of visited vertices.
• Once the DFS is completed, count the number of false in visited array. These are the vertices which did not get visit.

Run This Code

Code:

Output:

Number of non-reachable vertices from the vertex 0 are: 4
Number of non reachable vertices from the vertex 6 are: 5

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