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()
}

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

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

N, M = tuple(map(int, input().split()))
adj = [[] for n in range(N)]

for _ in range(M):
    inp = tuple(map(int, input().split()))
    adj[inp[0]].append(inp[1])
    adj[inp[1]].append(inp[0])

unsearched = set(range(N))
colors = {n:-1 for n in range(N)}
color = -1
while len(unsearched):
    color += 1
    start = min(unsearched)
    unsearched.remove(start)
    searched = set([start])
    
    que = deque([start])
    while len(que):
        q = que.pop()
        next_ = [i for i in adj[q] if  not (i in searched)]
        searched.update(next_)
        unsearched = unsearched.difference(searched)
        que.extendleft(next_)
    for n in searched:
        colors[n] = color
    
Q = int(input())

for i in range(Q):
    question = tuple(map(int, input().split()))
    if colors[question[0]] == colors[question[1]]:
        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] and friend_id[s] == friend_id[t] else'no')

Python: from collections import deque
n,m = map(int,input().split())
G = [[] for _ in range(n)]
for i in range(m):
    s,t = map(int,input().split())
    s -= 1
    t -= 1
    G[s].append(t)
    G[t].append(s)

uni = [-1]*n
stk = deque()
def dfs(u,c):
    stk.append(u)
    while stk:
        u = stk.pop()
        uni[u] = c
        for v in G[u]:
            if uni[v] != -1: continue
            stk.append(v)

c = 0
for i in range(n):
    if uni[i] == -1:
        dfs(i,c)
        c += 1

q = int(input())
ans = ["no"]*q
for i in range(q):
    s,t = map(int,input().split())
    s -= 1
    t -= 1
    if uni[s] == uni[t]: ans[i] = "yes"

print("\n".join(ans))

Python: #coding:utf-8
#16D8101012J Ito Jun dj Python3

class UnionFind:
    def __init__(self,n):
        self.parent=[i for i in range(n+1)]
        self.rank=[0]*(n+1)
    def find(self,x):
        if self.parent[x] == x: # if x is x`s root
            return x
        else:
            self.parent[x] = self.find(self.parent[x])
            return self.parent[x]
    def is_same_tree(self,x,y):
        return self.find(x) == self.find(y) 
    def union(self,x,y):
        x=self.find(x)
        y=self.find(y)
        if self.rank[x] < self.rank[y]:
            self.parent[x] = y
        else:
            self.parent[y] = x
        if self.rank[x] == self.rank[y]:
            self.rank[x] += 1
        
def main():
    n=list(map(int,input().split()))
    union=UnionFind(n[0])
    friends=[]
    question=[]
    for i in range(n[1]):
        a=tuple(map(int,input().split()))
        friends.append(a)
    for i in friends:
        union.union(i[0],i[1])
    m=int(input())
    for i in range(m):
        b=tuple(map(int,input().split()))
        question.append(b)
    for i in question:
        if union.find(i[0]) == union.find(i[1]):
            print("yes")
        else:
            print("no")
if __name__ == "__main__":
    main()

Python: # -*- coding: utf-8 -*-
from collections import deque
import sys
sys.setrecursionlimit(100000)


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")