/**
* Method testEulerian to check if the given graph is Eulerian or not. A Eulerian graph is
* connected and the degree of each vertes is even. They have a cycle, that goes through every
* edge of graph only once. A connected graph with exactly two vertices of odd degree has Eulerian
* Path.
*
* @param g: Input graph which is to be tested for satisfying Eulerian conditions
*/
static int testEulerian(Graph<Vertex> g) {
Vertex v1 = null, v2 = null;
int conn = dfsUtil(g);
if (conn > 1) {
System.out.println("The graph is not connected.");
System.exit(0);
}
int odd = 0;
for (Vertex u : g) {
if (u.Adj.size() % 2 != 0) {
odd++;
if (odd == 1) {
v1 = u;
} else if (odd == 2) {
v2 = u;
}
}
}
if (odd == 0) {
return 2;
} else if (odd == 2) {
System.out.println(v1 + " and " + v2);
return 1;
} else return 0;
}
/**
* Method to add an edge to the graph
*
* @param a : int - one end of edge
* @param b : int - other end of edge
* @param weight : int - the weight of the edge
*/
void addEdge(int a, int b, int weight) {
Vertex u = verts.get(a);
Vertex v = verts.get(b);
Edge e = new Edge(u, v, weight);
u.Adj.add(e);
v.Adj.add(e);
}