Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

// I/O
type Scanner struct {
	sc *bufio.Scanner
}

func NewScanner() *Scanner {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, 1024), int(1e+9))
	return &Scanner{sc}
}

func (s *Scanner) nextStr() string {
	s.sc.Scan()
	return s.sc.Text()
}

func (s *Scanner) nextInt() int {
	i, e := strconv.Atoi(s.nextStr())
	if e != nil {
		panic(e)
	}
	return i
}

func (s *Scanner) nextFloat() float64 {
	f, e := strconv.ParseFloat(s.nextStr(), 64)
	if e != nil {
		panic(e)
	}
	return f
}

func (s *Scanner) nextRuneSlice() []rune {
	return []rune(s.nextStr())
}

func (s *Scanner) nextIntSlice(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextInt()
	}
	return res
}

func (s *Scanner) nextFloatSlice(n int) []float64 {
	res := make([]float64, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextFloat()
	}
	return res
}

// Arithmetic
func max(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m < i {
			m = i
		}
	}
	return m
}

func min(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m > i {
			m = i
		}
	}
	return m
}

func abs(x int) int {
	if x > 0 {
		return x
	}
	return -x
}

func pow(x, y int) int {
	res := 1
	for i := 0; i < y; i++ {
		res *= x
	}
	return res
}

func ceil(a, b int) int {
	if a%b == 0 {
		return a / b
	} else {
		return a/b + 1
	}
}

// Sort
type RuneSlice []rune

func (a RuneSlice) Len() int           { return len(a) }
func (a RuneSlice) Less(i, j int) bool { return a[i] < a[j] }
func (a RuneSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }

// Main
func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	N, M := sc.nextInt(), sc.nextInt()
	G := make([][]int, N)
	for i := 0; i < M; i++ {
		s, t := sc.nextInt(), sc.nextInt()
		G[s] = append(G[s], t)
		G[t] = append(G[t], s)
	}
	group := make([]int, N)
	for i := 0; i < N; i++ {
		group[i] = -1
	}
	var dfs func(cur int)
	dfs = func(cur int) {
		for i := 0; i < len(G[cur]); i++ {
			next := G[cur][i]
			if group[next] == -1 {
				group[next] = group[cur]
				dfs(next)
			}
		}
	}
	num := 0
	for i := 0; i < N; i++ {
		if group[i] == -1 {
			group[i] = num
			dfs(i)
			num++
		}
	}

	Q := sc.nextInt()
	for i := 0; i < Q; i++ {
		s, t := sc.nextInt(), sc.nextInt()
		if group[s] == group[t] {
			fmt.Fprintln(wtr, "yes")
		} else {
			fmt.Fprintln(wtr, "no")
		}
	}
	wtr.Flush()
}

C++: #include<bits/stdc++.h>
using namespace std;

const int INF=99999999;

vector<int> A[100000];

void get_network(int N,int M){
    int s,t;
    for(int i=0;i<M;i++){
        cin>>s>>t;
        A[s].push_back(t);
        A[t].push_back(s);
    }
}
void bfs(int n,int v,vector<int>& flag,int mark){
        queue<int> Q;
        flag[v]=mark;
        for(int i=0;i<A[v].size();i++){
                Q.push(A[v][i]);
        }
        while(!Q.empty()){
                int u=Q.front();
                flag[u]=mark;
                for(int i=0;i<A[u].size();i++){
                        if(flag[A[u][i]]==-1){
                                Q.push(A[u][i]);
                        }
                }
                Q.pop();
        }
}

int main(){
        int n,m;
        scanf("%d %d\n",&n,&m);
        get_network(n,m);

        vector<int> flag(n,-1);
        int colored=-1;
        int v=0;
        int mark=0;
        while(colored!=0){
                mark++;
                bfs(n,v,flag,mark);
                colored=0;
                for(int i=0;i<flag.size();i++){
                    if(flag[i]==-1){
                        v=i;
                        colored=1;
                        break;
                    }
                }
        }

        int q,s,t;
        scanf("%d\n",&q);

        for(int i=0;i<q;i++){
                scanf("%d %d\n",&s,&t);
                if(flag[s]==flag[t]){
                        printf("yes\n");
                }else{
                        printf("no\n");
                }
        }
        return 0;
}

C++: #include <iostream>
#include <string>
#include <stdio.h>
#include <vector>
#include <stack>
#include <queue>
#define N 100000
using namespace std;


int C[N];
queue<int> k;
vector<int> v[N];
void color(int);
bool search(int,int);

int main(){
	int n,m,a,b,q;
	cin >> n >>m;
	for(int i=0;i<m;i++){
		cin >> a >> b;
		v[a].push_back(b);
		v[b].push_back(a);
	}
	cin >> q;
	for(int i=0;i<n;i++){
		C[i]=-1; //?????????
	}
	for(int i=0;i<n;i++){
		if(C[i]==-1)color(i); //i????§??????¨????????±???
	}
	for(int i=0;i<q;i++){
		cin>>a>>b;
		if(search(a,b)) cout<<"yes"<<endl;
		else cout<<"no"<<endl;
	}
	return 0;
}

bool search(int a,int b){
	if(C[a]==C[b]) return true;
	else return false;
}

void color(int a){
	static int c=0;
	c++;
	C[a]=c;
	k.push(a);
	while(!k.empty()){
		int m = k.front();
		k.pop();
		for(int i=0;i<v[m].size();i++){
			int Z= v[m].at(i);
			if(C[Z]==-1){
				C[Z]=c;
				k.push(Z);
			}
		}
	}
}

C++: #include<iostream>
#include<cstdio>
#include<cstdlib>
#include<string.h>
#include<stack>
#include<queue>
#include<vector>
using namespace std;

int n, m;
int d[100000];
int t = 0;
int c[100000];
queue<int> q;
vector<int> v[100000];
int ans = 2;

void bfs(int u){
  q.push(u);
  c[u] = 1;

  while(q.empty() == 0){
    u = q.front();
    q.pop();
    for(int i = 0; i < v[u].size(); i++){
      if(c[v[u][i]] == 0){
        q.push(v[u][i]);
        c[v[u][i]] = 1;
      }

    }
    c[u] = ans;
  }

}


int main(){

  cin >> n;

  for(int i = 0; i < n; i++){
    c[i] = 0;
  }

  cin >> m;

  for(int i = 0; i < m; i++){
    int x, y;
    cin >> x >> y;
    v[x].push_back(y);
    v[y].push_back(x);
  }

  for(int i = 0; i < n; i++){
    if(c[i] == 0){
      bfs(i);
      ans++;
    }
  }

  int q;
  cin >> q;

  for(int i = 0; i < q; i++){
    int x, y;
    cin >> x >> y;
    if(c[x] == c[y]) cout << "yes" << endl;
    else cout << "no" << endl;
  }

  return 0;
}

C++: #include <iostream>
#include <vector>
#define N 100000
#define white 0
using namespace std;

int color[N], n, S[N];
vector<int> c[N];



void tansaku_2(int a, int b) {
    int i, t, co, u;
    S[0] = a;
    t = 0;
    co = 1;
    while (1) {
        u = S[t];
        for (i = 0; i < c[u].size(); ++i) {
            if (color[c[u][i]] == white){
                color[c[u][i]] = b;
                S[co++] = c[u][i];
            }
        }
        S[t++] = 0;
        if (t == co) break;
    }
}

void tansaku() {
    int i, d;
    d = 1;
    
    for (i = 0; i < n; ++i) {
        if (color[i] == white) {
            color[i] = d;
            tansaku_2(i , d++);
        }
    }
}

int main() {
    int m, q, i, a, b;
    
    cin >> n >> m;
    for (i = 0; i < n; ++i) {
        color[i] = white;
    }
    for (i = 0; i < m; ++i) {
        scanf("%d %d", &a, &b);
        c[a].push_back(b);
        c[b].push_back(a);
    }
    tansaku();
    
    cin >> q;
    
    for (i = 0; i < q; ++i) {
        scanf("%d %d", &a, &b);
        if (color[a] == color[b]) {
            cout << "yes" << endl;
        }
        else{
            cout << "no" << endl;
        }
    }
    return 0;
}