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.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.InputMismatchException;
import java.util.List;
import java.util.StringTokenizer;

public class Main {
	static class ConnectedComponents {
		public void CC (InputReader ir) {
			
			int n = ir.nextInt();
			int m = ir.nextInt();
			SNS[] sns = new SNS[n];
			
			for (int i = 0; i < n; i++) {
				sns[i] = new SNS ();
			}
			
			for (int i = 0; i < m; i++) {
				int id = ir.nextInt();
				int t = ir.nextInt();
				sns[id].friend.add(t);
				sns[t].friend.add(id);
				
			}
			
			int q = ir.nextInt();
			
			for (int i = 0; i < q; i++) {
				int s = ir.nextInt();
				int t = ir.nextInt();
				if (cc (sns, s, t)) System.out.println("yes");
				else System.out.println("no");
				for (int j = 0; j < n; j++) {
					sns[j].dis = null;
				}
				
			}
			
		}
		
		public boolean cc (SNS[] sns, int s, int t) {
			
			if ( s == t) return true;

			if (sns[s].dis == null) {
				sns[s].dis = 0;
				if (sns[s].friend != null) {
					for (int i = 0; i < sns[s].friend.size(); i++) {
						if (cc (sns, sns[s].friend.get(i), t)) return true;
					}
				}
			}
			
			
			return false;
			
		}
		
	}
	
	static class SNS {
		List<Integer> friend = new ArrayList<> ();
		Integer dis;
		SNS (){
			dis = null;
		}
	}
	
	static class InputReader {
		BufferedReader br;
		StringTokenizer st;
		
		public String nextString() {
			
			 while (!st.hasMoreTokens()) {
	                try {
	                    st = new StringTokenizer(br.readLine(), " ");
	                } catch (IOException e) {
	                    throw new InputMismatchException();
	                }
	            }
			return st.nextToken();
		}
		
		public int nextInt() {
			return Integer.parseInt(nextString());
		}
					
		public InputReader (InputStream inputStream) {
			br = new BufferedReader (new InputStreamReader (inputStream));
			st = new StringTokenizer ("");
		}
		
	}
	
	public static void main (String[] args) {
		InputStream inputStream = System.in;
		InputReader in = new InputReader (inputStream);
		ConnectedComponents obj = new ConnectedComponents ();
		obj.CC (in);
	}
	
	
}