Problem:
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Connected Components

Write a program which reads relations in a SNS (Social Network Service), and judges that given pairs of users are reachable each other through the network.

Input

In the first line, two integer $n$ and $m$ are given. $n$ is the number of users in the SNS and $m$ is the number of relations in the SNS. The users in the SNS are identified by IDs $0, 1, ..., n-1$.

In the following $m$ lines, the relations are given. Each relation is given by two integers $s$ and $t$ that represents $s$ and $t$ are friends (and reachable each other).

In the next line, the number of queries $q$ is given. In the following $q$ lines, $q$ queries are given respectively. Each query consists of two integers $s$ and $t$ separated by a space character.

Output

For each query, print "yes" if $t$ is reachable from $s$ through the social network, "no" otherwise.

Constraints

$2 \leq n \leq 100,000$

$0 \leq m \leq 100,000$

$1 \leq q \leq 10,000$

Sample Input

10 9
0 1
0 2
3 4
5 7
5 6
6 7
6 8
7 8
8 9
3
0 1
5 9
1 3

Sample Output

yes
yes
no

Solution in Scala (judge verdict: Accepted)

import scala.io.StdIn.{readLine, readInt};
import scala.annotation.tailrec;
import scala.collection.immutable.Queue;

object Main {
    def main(args: Array[String]): Unit = {
        val input = readLine.split(" ").map(_.toInt);
        val size = input(0);
        val relationNum = input(1);
        val g = new Graph(size);
        (0 until relationNum).foreach { i =>
            readLine.split(" ").map(_.toInt) match {
                case Array(src, dst) => g.add(src, dst);
                case _ => ();
            }
        }
        g.createConnectedList();
        val f = (a: Int, b: Int) => a == b;
        (0 until readInt).foreach { i =>
            readLine.split(" ").map(_.toInt) match {
                case Array(src, dst) => if (g.isSameGroup(src, dst)) println("yes") else println("no");
                case _ => ()
            }
        }
        
    }
}

class Graph(val size: Int) {
    val al = new Array[List[Int]](size);
    val visited = new Array[Int](size);

    def dump = al.zipWithIndex.filterNot(a => a._1 == null).foreach { e => println("%d -> %s".format(e._2, e._1.mkString(" ")))}

    def add(src: Int, dst: Int): Unit = {
        al(src) = dst :: (if (al(src) == null) Nil else al(src));
        al(dst) = src :: (if (al(dst) == null) Nil else al(dst));
    }
    
    def isSameGroup(n1: Int, n2: Int) = if (visited(n1) == visited(n2) && visited(n1) != 0 && visited(n2) != 0) true else false;
    
    def createConnectedList(): Unit = {
        @tailrec
        def _bfs(que: Queue[Int], group: Int): Unit = que.dequeueOption match { // 幅優先での探索
            case None => ();
            case Some((curr, que1)) => {
                val nextNodes = if (al(curr) == null) Nil else al(curr);
                val nextQue = nextNodes.filter(visited(_) == 0).
                    foldLeft(que1) { (tmpQue, nextNode) =>
                        visited(nextNode) = group;
                        tmpQue.enqueue(nextNode);
                    }
                _bfs(nextQue, group);
            }
        }
        (0 until size).foreach { i =>
            if (al(i) != null && visited(i) == 0) {
                visited(i) = i + 1;
                _bfs(Queue[Int](i), i + 1);
            }
        }
    }
}