Problem:
MathJax.Hub.Config({ tex2jax: { inlineMath: [["$","$"], ["\\(","\\)"]], processEscapes: true }});

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 C# (judge verdict: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
    class User
    {
        internal int group;
        internal List<int> friends;

        public User()
        {
            group = -1;
            friends = new List<int>();
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            int[] input = Array.ConvertAll(Console.ReadLine().Split(' '), int.Parse);
            int n = input[0], m = input[1];

            User[] users = new User[n];
            for (int i = 0; i < n; i++) users[i] = new User();

            for (int i = 0; i < m; i++)
            {
                input = Array.ConvertAll(Console.ReadLine().Split(' '), int.Parse);

                users[input[0]].friends.Add(input[1]);
                users[input[1]].friends.Add(input[0]);
            }
            
            for(int i = 0; i < n; i++)
            {
                if (users[i].group == -1) DFS(users, i, i);
            }

            StringBuilder sb = new StringBuilder();
            int q = int.Parse(Console.ReadLine());

            for (int i = 0; i < q; i++)
            {
                input = Array.ConvertAll(Console.ReadLine().Split(' '), int.Parse);

                sb.AppendLine(users[input[0]].group == users[input[1]].group ? "yes" : "no");
            }
            Console.Write(sb);
        }

        static void DFS(User[] U, int u, int g)
        {
            Stack<User> stk = new Stack<User>();
            U[u].group = g;
            stk.Push(U[u]);

            while (stk.Count > 0)
            {
                User temp = stk.Pop();

                foreach (var friend in temp.friends)
                {
                    if (U[friend].group == -1)
                    {
                        U[friend].group = g;
                        stk.Push(U[friend]);
                    }
                }
            }
        }
    }
}