Go: package main

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

const MAX = 100000

type Queue struct {
	head      int
	tail      int
	container [MAX]int
}

func (q *Queue) push(n int) {
	q.container[q.tail] = n
	q.tail = (q.tail + 1) % MAX
}

func (q *Queue) pop() int {
	res := q.container[q.head]
	q.head = (q.head + 1) % MAX
	return res
}

func (q *Queue) isEmpty() bool {
	return q.head == q.tail
}

var sc = bufio.NewScanner(os.Stdin)
var route [][]int
var SEEN [MAX]bool
var GROUP [MAX]int

func scanInt() int {
	num, _ := strconv.Atoi(scanString())
	return num
}

func scanString() string {
	sc.Scan()
	return sc.Text()
}

func init() {
	sc.Split(bufio.ScanWords)
}

func bfs(start, group int) {
	que := Queue{}
	que.push(start)

	for !que.isEmpty() {
		id := que.pop()

		if SEEN[id] {
			continue
		}
		SEEN[id] = true
		GROUP[id] = group

		for _, next := range route[id] {
			que.push(next)
		}
	}
}

func main() {
	n, m := scanInt(), scanInt()
	route = make([][]int, n)
	for i := 0; i < m; i++ {
		s, t := scanInt(), scanInt()
		route[s] = append(route[s], t)
		route[t] = append(route[t], s)
	}

	for i := 0; i < n; i++ {
		if !SEEN[i] {
			bfs(i, i+1)
		}
	}

	w := bufio.NewWriter(os.Stdout)
	q := scanInt()
	for i := 0; i < q; i++ {
		s, t := scanInt(), scanInt()
		if GROUP[s] == GROUP[t] {
			fmt.Fprintln(w, "yes")
		} else {
			fmt.Fprintln(w, "no")
		}
	}
	w.Flush()
}

Python: def dfs(G, s):
    # ????????????
    S = [s]
    # ?¨??????????????????????
    C = set([s])
    while len(S) > 0:
        v = S.pop()
        for w in G[v]:
            if w not in C:
                S.append(w)
                C |= set([w])
    return C


if __name__ == '__main__':
    n, m = map(int, input().split())
    G = {key: [] for key in range(n)}
    for i in range(m):
        s, t = map(int, input().split())
        G[s].append(t)
        G[t].append(s)

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

Python: 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)

isVisited = [False] * n

CC = [None] * n


def dfs(u, group):
    isVisited[u] = True
    CC[u] = group
    for v in adj[u]:
        if not isVisited[v]:
            dfs(v, group)

def makeCC(group):
    for i in range(n):
        if not isVisited[i]:
            dfs(i, group)
            group += 1

def isConnected(v1, v2):
    if CC[v1] == CC[v2]:
        print('yes')
    else:
        print('no')


makeCC(0)


q = int(input())

for i in range(q):
    s, t = map(int, input().split())
    isConnected(s, t)

Python: def DFS(s):
    flag[s] = 1
    group[s] = j
    for i in range(n):
        if i in G[s] and flag[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 = [[] for i in range(n)]
flag = [0 for i in range(n)]
j = 0
for i in range(n):
    if flag[i] == 0:
        DFS(i)
        j += 1

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

Python: # -*- coding: utf-8 -*-
from collections import deque


if __name__ == '__main__':

    n, m = [int(s) for s in input().split(" ")]
    M = [set() for j in range(n)]
    for _ in range(m):
        u, v = [int(s) for s in input().split(" ")]
        M[u].add(v)
        M[v].add(u)
        
    color = [0] * n
    def dfs(u, c):  # depth-first search
        color[u] = c
        for v in M[u]:
            if color[v] == 0:
                dfs(v, c)
    
    c = 1
    for u in range(n):
        if color[u] == 0:
            dfs(u, c)
            c += 1
    
    l = int(input())
    for _ in range(l):
        p, q = [int(s) for s in input().split(" ")]
        if color[p] == color[q]:
            print("yes")
        else:
            print("no")

Python: n, m = map(int, input().split())
relations = [[] for _ in range(n)]

for i in range(m):
    s, t = map(int, input().split())
    if s > t:
        s, t = t, s
    relations[s] += [t]
friend_id = [None] * n
for s, t in enumerate(relations):
    if t:
        queue = [s]
        while len(queue):
            k = queue.pop()
            friend_id[k] = s
            queue += relations[k]
            relations[k] = []

q = int(input())
for i in range(q):
    s, t = map(int, input().split())
    print('yes' if friend_id[s] != None and friend_id[s] == friend_id[t] else'no')

Python: # -*- coding: utf-8 -*-
from collections import deque


if __name__ == '__main__':

    n, m = [int(s) for s in input().split(" ")]
    M = [set() for j in range(n)]
    for _ in range(m):
        u, v = [int(s) for s in input().split(" ")]
        M[u].add(v)
        M[v].add(u)
        
    color = [0] * n
    def dfs(u, c):  # depth-first search
        color[u] = c
        for v in range(n):
            if v in M[u] and color[v] == 0:
                dfs(v, c)
        color[u] = c
    
    c = 1
    for u in range(n):
        if color[u] == 0:
            dfs(u, c)
            c += 1
    
    l = int(input())
    for _ in range(l):
        p, q = [int(s) for s in input().split(" ")]
        if color[p] == color[q]:
            print("yes")
        else:
            print("no")

Python: n, m = map(int, input().split())
import sys
sys.setrecursionlimit(1000000)
c_list = {}
# 辞書の初期化
for node in range(n):
    c_list[node] = []

for _ in range(m):
    a, b = map(int, input().split())
    c_list[a].append(b)
    c_list[b].append(a)

colors = {}


# 色を割り当てていく
def dfs(node, c):
    if node not in colors:
        colors[node] = c
        for next in c_list[node]:
            dfs(next, c)


# stackでも書きたい
# 色の割当が間違っている
def assignColor():
    c = 0
    for node in c_list:
        if node not in colors:
            dfs(node, c)
            c += 1


def checkColor(u, v):
    if colors[u] == colors[v]:
        print('yes')
    else:
        print('no')


assignColor()
k = int(input())
for _ in range(k):
    u, v = map(int, input().split())
    checkColor(u, v)

Python: n,m=map(int,input().split())
P=[[]for _ in[0]*n]
C=[0]*n
k=0
for _ in[0]*m:
 s,t=map(int,input().split());P[s]+=[t];P[t]+=[s]
for i in range(n):
 k+=1
 if C[i]<1:
  s=[i];C[i]=k
  while s:
   u=s.pop()
   for v in P[u]:
    if C[v]<1:C[v]=k;s+=[v]
for _ in[0]*int(input()):
 a,b=map(int,input().split())
 print(['no','yes'][C[a]==C[b]])

Python: 
def BFS(s = 0, group_num = 0):
    Q.pop(0)
    color[s] = 2
    for j in range(len(A[s])):
        if color[A[s][j]] == 0:
            Q.append(A[s][j])
            color[A[s][j]] = 1
            affil[A[s][j]] = group_num
    if len(Q) != 0:
        BFS(Q[0], group_num)

entry1 = map(int, raw_input())
n = entry1[0]
m = entry1[1]

A = range(n)
for i in A:
    A[i] = list()
for i in range(m):
    entry2 = map(int, raw_input())
    s = entry2[0]
    t = entry2[1]
    A[s].append(t)
    A[t].append(s)

color = [0] * n
affil = [0] * n
group_num = -1
for i in range(n):
    if color[i] == 0:
        Q = [i]
        group_num = group_num + 1
        affil[i] = group_num
        BFS(i, group_num)

q = int(raw_input())
for i in range(q):
    entry3 = map(int, raw_input())
    if affil[entry3[0]] == affil[entry3[1]]:
        print("yes")
    else:
        print("no")