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: Wrong Answer)

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayDeque;
import java.util.LinkedList;
import java.util.List;
import java.util.Vector;

public class Main {

	public static void main(String[] args) throws NumberFormatException, IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String[] str = br.readLine().split(" ");
		int n = Integer.parseInt(str[0]);
		int m = Integer.parseInt(str[1]);
		
		List<List<Integer>> a = new Vector<List<Integer>>(n);
		for(int i = 0; i < n; ++i) {
			a.add(new LinkedList<Integer>());
		}
		
		int u, v;
		for(int i = 0; i < m; i++) {
			str = br.readLine().split(" ");
			u = Integer.parseInt(str[0]);
			v = Integer.parseInt(str[1]);
			
			a.get(u).add(v);
			a.get(v).add(u);
		}

		// classify nodes
		int[] d = new int[n];
		int no = 0;
		ArrayDeque<Integer> st = new ArrayDeque<Integer>(); // stack
		for(int i = 0; i < n; ++i) {
			if(d[i] != 0){
				continue;
			}
			no += 1;
			st.push(i); // first node
			while(st.size() > 0){
				for(Integer node: a.get(st.pop())){
					if(d[node] == 0){
						// push the adjacent nodes
						d[node] = no;
						st.push(node);
						
					}
				}
			}
			
		}
		
		// read Q's
		int q = Integer.parseInt(br.readLine());
		StringBuilder sb = new StringBuilder();
		for(int i = 0; i < q; i++){
			str = br.readLine().split(" ");
			if(d[Integer.parseInt(str[0])] == d[Integer.parseInt(str[1])]){
				sb.append("yes\n");
			}else{
				sb.append("no\n");
			}
		}
		System.out.print(sb);
	}

}