Edge Labeling

Warning

NOT TESTED

#include <cstdio>
#include <vector>

using namespace std;

#define MAX 100

enum States {UNVISITED, VISITED, EXPLORED};

/*
    UNVISTED - not visited yet
    VISTED   - visited and all edges checked
    EXPLORED - visited but with unchecked edges
*/

int parent_node[MAX];
States node_state[MAX];
vector<int> G[MAX];

void graphCheck(int node)
{
    /*
        Maps every edge on a graph
        Useful for cycle detection
        Complexity: O(E + V)
    */

    node_state[node] = EXPLORED;

    for(auto adjacent: G[node])
    {
        // Edge: EXPLORED -> UNVISTED
        if(node_state[adjacent] == UNVISITED)
        {
            parent_node[adjacent] = node;
            graphCheck(adjacent);
        }
        // Edge: EXPLORED -> EXPLORED
        else if(node_state[adjacent] == EXPLORED)
        {
            if(adjacent == parent_node[node])
            {
                // Undirected / Two ways
            }
            else
            {
                // Back edge / Cycle
            }
        }
        // Edge: EXPLORED -> VISITED
        else if(node_state[adjacent] == VISITED)
        {
            // Foward Edge / Cycle / Cross Edge
        }
    }

    node_state[node] = VISITED;
}