public static int degree(Graph G, int v) {
int degree = 0;
for (int w : G.adj(v)) degree++;
return degree;
}
public static int numberOfSelfLoops(Graph G) {
int count = 0;
for (int v = 0; v < G.V(); v++) for (int w : G.adj(v)) if (v == w) count++;
return count / 2;
}