Weighted Quick Union Find Algorithm

public class WeightedQuickUnionUF {
 private int[] id;
 private int[] size;

 public WeightedQuickUnionUF(int N) {
  id = new int[N];
  size =  new int[N];
  for (int i = 0; i < N; i++) {
   id[i] = i;
   size[i] = 0;
  }
 }

 private int root(int i) {
  while (i != id[i])
   i = id[i];
  return i;
 }

 //log(N)
 public boolean connected(int p, int q) {
  return root(p) == root(q);
 }
 //log(N)
 public void union(int p, int q) {
  int i = root(p);
  int j = root(q);
  if (i == j)
   return;
  if (size[i] < size[j]) {
   id[i] = j;
   size[j] += size[i];
  } else {
   id[j] = i;
   size[i] += size[j];
  }
 }
}

public class Main {

 public static void main(String[] args) {
  Scanner in = new Scanner(System.in);
  int N = in.nextInt();  
  WeightedQuickUnionUF wQuickUnionUF = new WeightedQuickUnionUF(N);
  while (in.hasNext()) {
   int p = in.nextInt();
   int q = in.nextInt();
   if (!wQuickUnionUF.connected(p, q)) {
    wQuickUnionUF.union(p, q);
   } else
    System.out.println("Already Connected");
  }
 }

}