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 JAVA (judge verdict: Runtime Error)

import java.util.Scanner;
import java.util.ArrayList;
import java.util.Hashtable;
public class Main {
	public static void main(String[] args) {
		Scanner input = new Scanner(System.in);
		int nodes = input.nextInt();
		int connections = input.nextInt();
		Hashtable<Integer, ArrayList<Integer>> hash = new Hashtable<Integer, ArrayList<Integer>>();
		for(int i = 0; i < connections; i++) {
			int vertex = input.nextInt();
			int toVertex = input.nextInt();
			if(hash.containsKey(vertex)) {
				ArrayList<Integer> value = hash.get(vertex);
				value.add(toVertex);
				hash.put(vertex, value);
			}
			else {
				ArrayList<Integer> value = new ArrayList<Integer>();
				value.add(toVertex);
				hash.put(vertex, value);
			}
		}
		int tests = input.nextInt();
		int[][] testing = new int[tests][tests];
		for(int i = 0; i < tests; i++) {
			for(int j = 0; j < 2; j++) {
				testing[i][j] = input.nextInt();
			}
		}
		for(int i = 0; i < tests; i++) {
			viable(hash, testing[i][0], testing[i][1], new ArrayList<Integer>());
		}
	}
	public static void viable(Hashtable<Integer, ArrayList<Integer>> hash, int from, int to, ArrayList<Integer> checked) {
		boolean found = false;
		if(hash.get(from) != null) {
			checked.add(from);
			if(hash.get(from).contains(to)) {
				System.out.println("yes");
				found = true;
				return;
			}
			else {
				for(int i = 0; i < hash.get(from).size(); i++) {
					from = hash.get(from).get(i);
					viable(hash, from, to, checked);
				}
			}
		}else {
			System.out.println("no");
		}
	}
}