Question

I am trying to implement a recursive depth first traversal on a weighted digraph(, but it seems as if my output is always off. As in, I am getting extra visits to nodes. This is what I am currently working with:

void Dfs( int u, vector<bool> visited, vector < char > label, vector < vector < int > > adj)
{
visited[u] = true;
cout << label[u];

for ( int i = 0; i < (signed)visited.size(); i++)
    {
    if (visited[i] != true && adj[u][i] != 0)
            {
            cout << "->";
            Dfs( i, visited, label, adj);
            }
    }

}

Where label is the letter assigned to the verticies (A = 0, etc…), visited is a vector holding whether or not the vertex at a certain index has been visited, and adj is the adjacency matrix.

Say I have a graph and the correct depth first search is A->D->B->C->E, what I end up getting is A->D->B->C->E->C->B->E. If it helps, for this example the adjacency matrix looks like:

  |  A  B  C  D  E
--|---------------
A |  -  -  -  6  -
B |  -  -  8  3  2
C |  -  8  -  7  -
D |  6  3  7  -  -
E |  -  2  -  -  -

Answer 1

The parameters to your function are pass by value; so your visited vector is not getting updated. Also, use pass by reference for your other vectors so that each recursive call is not copying the vectors.