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: Runtime Error)

// ミュータブル
import scala.io.StdIn.{readLine, readInt};
import scala.annotation.tailrec;
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 AdjacentListGraph[Int](size);
        (0 until relationNum).foreach { i =>
            readLine.split(" ").map(_.toInt) match {
                case Array(src, dst) => g.add(src, dst);
                case _ => ();
            }
        }
        val f = (a: Int, b: Int) => a == b;
        (0 until readInt).foreach { i =>
            readLine.split(" ").map(_.toInt) match {
                case Array(src, dst) => if (g.bfs(src, dst)) println("yes") else println("no");
                case _ => ()
            }
        }
        
    }
}
class AdjacentListGraph[A](val size: Int) {
    val al = scala.collection.mutable.HashMap[A, List[A]]();

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

    def add(src: A, dst: A): Unit = {
        al.put(src, dst :: al.getOrElse(src, Nil));
        al.put(dst, src :: al.getOrElse(dst, Nil));
    }
    def bfs(src: A, dst: A): Boolean = {
        val vMap = scala.collection.mutable.HashMap[A, Int]();
        val que = new Queue[A](size);
        @tailrec
        def _bfs(): Boolean = que.deque match { // 幅優先での探索
            case None => false;
            case Some(curr) => {
                val exists = al.getOrElse(curr, Nil).
                    filterNot(vMap.isDefinedAt(_)).
                    find { child => if (child == dst) {
                            true
                        } else {
                            que.enque(child);
                            vMap.put(child, 1);
                            false;
                        } 
                    }
                if (exists == None) _bfs() else true;
            }
        }
        que.enque(src);
        vMap.put(src, 1);
        if (src == dst) true else _bfs();
    }
}
class Queue[A](size: Int){
    var inPtr = 0;
    var outPtr = 0;
    var cnt = 0;
    val q = new scala.collection.mutable.ArraySeq[A](size)
    
    def isEmpty: Boolean = cnt == 0;
    
    def isFull: Boolean = cnt == size;
    
    def enque(elem: A): Boolean = if (isFull) false else {
        q(inPtr) = elem;
        inPtr = if (inPtr == (size - 1)) 0 else inPtr + 1;
        cnt += 1;
        true;
    }
    
    def deque(): Option[A] = if (isEmpty) None else {
        val elem = q(outPtr);
        outPtr = if (outPtr == size - 1) 0 else outPtr + 1;
        cnt -= 1;
        Some(elem);
    }
}