Go: package main

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

// Node 頂点
type Node struct {
	gid  int   // グループID
	edge []int // 隣接辺
}

// NoID グループIDなし
const NoID = -1

// NewNode 頂点の生成
func NewNode() *Node {
	return &Node{gid: NoID, edge: []int{}}
}

func parseNode(nodes []*Node, gid int, queue []int) {
	if len(queue) == 0 {
		return
	}
	var nextQ []int
	for _, id := range queue {
		node := nodes[id]
		if node.gid == NoID {
			node.gid = gid
			for _, edge := range node.edge {
				nextQ = append(nextQ, edge)
			}
		}
	}
	parseNode(nodes, gid, nextQ)
	return
}
func digNode(nodes []*Node, id, gid int) {
	node := nodes[id]
	if node.gid != NoID {
		// 探索済み
		return
	}
	node.gid = gid
	for _, edge := range node.edge {
		digNode(nodes, edge, gid)
	}
	return
}

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	n, m := eGetInt2(scanner)

	nodes := make([]*Node, n)
	for i := 0; i < n; i++ {
		nodes[i] = NewNode()
	}

	for i := 0; i < m; i++ {
		a, b := eGetInt2(scanner)
		nodes[a].edge = append(nodes[a].edge, b)
		nodes[b].edge = append(nodes[b].edge, a)
	}

	for i := 0; i < n; i++ {
		// 幅優先探索
		// gid := i
		// queue := []int{i}
		// parseNode(nodes, gid, queue)

		// 深さ優先探索
		digNode(nodes, i, i)
	}

	q := eGetInt(scanner)
	for i := 0; i < q; i++ {
		a, b := eGetInt2(scanner)
		if nodes[a].gid == nodes[b].gid {
			fmt.Println("yes")
		} else {
			fmt.Println("no")
		}
	}
}

func eGetInt(scanner *bufio.Scanner) int {
	t := eAtoi(strings.Fields(eGetline(scanner)))
	return t[0]
}
func eGetInt2(scanner *bufio.Scanner) (int, int) {
	t := eAtoi(strings.Fields(eGetline(scanner)))
	return t[0], t[1]
}

func eGetline(p *bufio.Scanner) string {
	if !p.Scan() {
		if err := p.Err(); err != nil {
			log.Fatal(err.Error())
		}
		return ""
	}
	return p.Text()
}

func eAtoi(s []string) []int {
	ints := make([]int, len(s))
	var err error
	for i, e := range s {
		ints[i], err = strconv.Atoi(e)
		if err != nil {
			log.Fatal(err.Error())
		}
	}
	return ints
}

Python: import sys
class Union():
    def __init__(self, n):
        self.pre = [i for i in range(n)]
        self.rank = [1 for _ in range(n)]

    def union(self, a, b):
        aroot = self.find(a)
        broot = self.find(b)
        if aroot == broot:
            return
        if self.rank[aroot] < self.rank[broot]:
            aroot, broot = broot, aroot
        self.pre[broot] = self.pre[aroot]
        if self.rank[aroot] == self.rank[broot]:
            self.rank[aroot] += 1

    def find(self, n):
        while self.pre[n] != n:
            n = self.pre[n]
        return n

    def issame(self, a, b):
        if self.find(a) == self.find(b):
            return True
        return False

if __name__ == '__main__':
    m, n = map(int, sys.stdin.readline().split())
    union = Union(m)

    for _ in range(n):
        a, b = map(int, sys.stdin.readline().split())
        union.union(a, b)

    o = int(input())
    for _ in range(o):
        p, q = map(int, sys.stdin.readline().split())
        if union.issame(p, q):
            print('yes')
        else:
            print('no')

Python: def DFS(s):
    flag[s] = 1
    F[group].append(s)
    for i in range(n):
        if G[s][i] == 1:
            if flag[i] == 0:
                DFS(i)
 

n, m = map(int, input().split())
G = [[0 for i in range(n)] for j in range(n)]
for i in range(m):
    s, t = map(int, input().split())
    G[s][t] = 1
    G[t][s] = 1

F = []
flag = [0 for i in range(n)]
group = 0
for i in range(n):
    if flag[i] == 0:
        F.append([])
        DFS(i)
        group += 1

q = int(input())
ans = ["no" for i in range(q)]
for i in range(q):
    s, t = map(int, input().split())
    for friends in F:
        if s in friends and t in friends:
            ans[i] = "yes"

for i in range(q):
    print(ans[i])

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

N, M = tuple(map(int, input().split()))
adj = [[0]*(N) for _ in range(N)]

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

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 unsearched if adj[q][i]==1 and 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: entry = map(int, raw_input())
n = entry[0]
m = entry[1]
A = [] * n
for i in range(m):
    entry = map(int, raw_input())
    A[entry[0]].append(entry[1])
    A[entry[1]].append(entry[0])

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

Python: # -*- coding: utf_8 -*-

level = False
def debug(v):
    if level:
        print(v)

NOT_FOUND = 0
ENQUEUED = 1
FOUND = 2

def bfs(graph, start, target):
    debug(graph)
    if start == target:
        return True
    
    queue = []
    status = [NOT_FOUND] * len(graph)
    queue.append(start)

    while len(queue) != 0:
        debug("----------------------------")
        node = queue.pop(0)
        status[node] = FOUND
        edges = graph[node]
        debug(queue)
        debug(status)
        debug(edges)
        for e in edges:
            if e == target:
                return True
            if status[e] == NOT_FOUND:
                status[e] = ENQUEUED
                queue.append(e)

    return False

if __name__ == "__main__":
    n, m = [int(x) for x in input().split()]

    g = [[] for i in range(n)]
    for i in range(m):
        u, e = [int(x) for x in input().split()]
        g[u].append(e)
        g[e].append(u)

    n = int(input())
    for i in range(n):
        s, d = [int(x) for x in input().split()]
        if bfs(g, s, d):
            print("yes")
        else:
            print("no")

Python: #!/usr/bin/env python3
import sys
input = lambda: sys.stdin.readline()[:-1]
sys.setrecursionlimit(10**8)

n,m=map(int,input().split())
G=[[]*n for i in range(n)]
color=[-1]*n
for i in range(m):
    v1,v2=map(int,input().split())
    G[v1].append(v2)
    G[v2].append(v1)


def dfs(v,c):
    color[v]=c
    for vi in G[v]:
        if color[vi]==-1:
            dfs(vi,i)


for i in range(n):
    if color[i]==-1:
        dfs(i,i)

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