Go: package main

import (
	"fmt"
	"os"
	"bufio"
	"strconv"
	"container/list"
	"bytes"
)

const MaxNode int = 1e5

var graph [][] int
var color []int
var N int

func bfs(u, c int) {
	l := list.New()
	l.PushBack(u)
	for ;l.Len()!=0; {
		u = l.Front().Value.(int)
		color[u] = c
		l.Remove(l.Front())
		for i:=0; i<len(graph[u]); i++ {
			if color[graph[u][i]] == 0 {
				l.PushBack(graph[u][i])
			}
		}
	}
}

func assignColor() {
	id := 1
	for u:=0; u<N; u++ {
		if color[u] == 0 {
			bfs(u, id)
			id ++
		}
	}
}

func nextInt(scanner *bufio.Scanner) int {
	scanner.Scan()
	num, _ := strconv.Atoi(scanner.Text())
	return num
}


func buildGraph(scanner *bufio.Scanner) {
	N = nextInt(scanner)
	color = make([]int, N)
	graph = make([][]int, N)
	m := nextInt(scanner)
	for i:=0; i<m; i++ {
		n1 := nextInt(scanner)
		n2 := nextInt(scanner)
		graph[n1] = append(graph[n1], n2)
		graph[n2] = append(graph[n2], n1)
	}
}

func answer(scanner *bufio.Scanner) {
	var outBuffer bytes.Buffer
	cnt := nextInt(scanner)
	for i:=0; i<cnt; i++ {
		n1 := nextInt(scanner)
		n2 := nextInt(scanner)
		if color[n1] == color[n2] {
			outBuffer.WriteString("yes\n")
		} else {
			outBuffer.WriteString("no\n")
		}
	}
	fmt.Printf("%s", outBuffer.String())
}

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)
	buildGraph(scanner)
	assignColor()
	answer(scanner)
}

Python: from collections import deque

n, m = map(int, input().split())
g = [set() for _ in range(n)]

while m:
    s, t = map(int, input().split())
    g[s].add(t)
    g[t].add(s)
    m -= 1


def find(s, t):
    global g
    queue = deque()
    queue.append((0, s))
    queue.append((1, t))
    visited = (set(), set())
    visited[0].add(s)
    visited[1].add(t)

    def remember(visited, new):
        g[new] |= visited
        for v in visited:
            g[v].add(new)
        visited.add(new)

    while queue:
        st, i = queue.popleft()
        for f in g[i]:
            if f in visited[not st]:
                return True
            if f not in visited[st]:
                remember(visited[st], f)
                queue.append((st, f))
    return False


q = int(input())
while q:
    s, t = map(int, input().split())
    print('yes' if find(s, t) else 'no')
    q -= 1

Python: def DFS(s):
    group[s] = j
    for i in range(n):
        if i in G[s] and group[i] == 0:
            DFS(i)

n, m = map(int, input().split())
G = [[] for j in range(n)]

for i in range(m):
    s, t = map(int, input().split())
    G[s].append(t)
    G[t].append(s)

group = [0 for i in range(n)]
j = 1
for i in range(n):
    if group[i] == 0:
        DFS(i)
        j += 1

q = int(input())
for i in range(q):
    s, t = map(int, input().split())
    if group[s] == group[t]:
        print("yes")
    else:
        print("no")

Python: from collections import deque
 
n, m = map(int, input().split())

adj = [[] for _ in range(n)] # adjacent list

for _ in range(m):
    u, v = map(int, input().split())
    adj[u].append(v)
    adj[v].append(u)

c = ['w']*n # color of each vertex
con = [0]*n
cnt = 0


def BFS_visit(s):
    global c
    global cnt
    global con
    
    c[s] = 'g'
    con[s] = cnt
    
    Q = deque()
    Q.append(s)
    while Q:
        u = Q.popleft()
        for v in adj[u]:
            if c[v] == 'w':
                c[v] = 'g'
                con[v] = cnt
                Q.append(v)
        c[u] = 'b'
        
for u in range(n):
    if c[u] == 'w':
        cnt += 1
        BFS_visit(u)
        
        
q = int(input())
for _ in range(q):
    u, v = map(int, input().split())
    ans = "yes" if (con[u] == con[v]) else "no"
    print(ans)

Python: def main():
    n, m = map(int, input().split())
    adj = [[] for i in range(n)]
    for i in range(m):
        s, t = map(int, input().split())
        adj[s].append(t)
        adj[t].append(s)

    q = int(input())
    component_ids = [-1 for i in range(n)]
    id = 0
    for i in range(n):
        if component_ids[i] != -1:
            continue
        bfs(i, id, adj, component_ids)
        id += 1

    for i in range(q):
        s, t = map(int, input().split())
        if component_ids[s] == component_ids[t]:
            print("yes")
        else:
            print("no")


def bfs(node, id, adj, component_ids):
    que = [node]
    while que:
        u = que.pop(0)
        component_ids[u] = id
        for v in adj[u]:
            if component_ids[v] == -1:
                que.append(v)

main()

Python: from collections import deque
n,m = [int(i) for i in input().split()]
F = [{} for i in range(n)]
for _ in range(m):
    i,j = [int(i) for i in input().split()]
    F[i][j] = 1
    F[j][i] = 1
q = int(input())
DP = [0 for i in range(n)]
c = 1
d = deque()
for i in range(n):
    if not DP[i]:
        d.append(i)
    while(len(d)>0):
        tmp = d.pop()
        DP[tmp] = c
        for i in F[tmp]:
            if not DP[i]:
                d.append(i)
    c+=1

for i in range(q):
    s,t = [int(i) for i in input().split()]
    if DP[s] == DP[t]:
        print("yes")
    else:
        print("no")

Python: n, m = map(int, input().split())
G = [[] for j in range(n)]
for i in range(m):
    s, t = map(int, input().split())
    G[s].append(t)
    G[t].append(s)

group = []
c = 0
for i in range(n):
    group.append([])
    if not i in group:
        que = [i]
        group[i] = c
        while len(que) > 0:
            u = que[0]
            for j in G[u]:
                if not j in group:
                    group[j] = que.append(j)
            del que[0]
        c += 1

q = int(input())
for i in range(q):
    s, t = map(int, input().split())
    if group[s] == group[t]:
        print("yes")
    else:
        print("no")

Python: from sys import stdin
input = stdin.readline

from collections import deque, defaultdict
from copy import deepcopy

MAX = 100000
NIL = -1

# Gはdictで管理する、valueはdeque
G = defaultdict(lambda: deque())
color = [NIL]*MAX

def dfs(r, c):
    S = deque()
    S.append(r)
    color[r] = c
    while S:
        u = S.popleft()
        for v in G[u]:  # Gのvalueはdequeなので、それをvに一つずつ入れていく
            if color[v] == NIL:
                color[v] = c
                S.append(v)

def assign_color():
    id = 1
    for u in range(n):
        if color[u] == NIL:
            dfs(u, id)
            id += 1

n, m = map(int, input().split())

for _ in range(m):
    s, t = map(int, input().split())
    G[s].append(t)
    G[t].append(s)

assign_color()

q = int(input())
for _ in range(q):
    s, t = map(int, input().split())
    if color[s] == color[t]:
        print('yes')
    else:
        print('no')

Python: n, m = map(int, input().split())
G = [[] for j in range(n)]
for i in range(m):
    s, t = map(int, input().split())
    G[s].append(t)
    G[t].append(s)

group = [[] for i in range(n)]
c = 0
for i in range(n):
    if not i in group:
        que = [i]
        group[i] = c
        while len(que) > 0:
            u = que[0]
            for j in G[u]:
                if not j in group:
                    group[j] = que.append(j)
            del que[0]
        c += 1

q = int(input())
for i in range(q):
    s, t = map(int, input().split())
    if group[s] == group[t]:
        print("yes")
    else:
        print("no")