Go: // AOJ ALDS1_11_D: http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=ALDS1_11_D

package main

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

var nocolor = -1

type graph struct {
	graph  [][]int
	colors []int
}

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

func newGraph(nodeNum int) *graph {
	colors := make([]int, nodeNum)
	g := make([][]int, nodeNum)
	for i := 0; i < nodeNum; i++ {
		g[i] = []int{}
		colors[i] = nocolor
	}

	return &graph{g, colors}
}

func constructGraph(sc *bufio.Scanner) *graph {
	usersNum := nextInt(sc)
	linkNum := nextInt(sc)

	g := newGraph(usersNum)
	for i := 0; i < linkNum; i++ {
		u := nextInt(sc) // node
		l := nextInt(sc) // link node
		// edge each other
		g.graph[u] = append(g.graph[u], l)
		g.graph[l] = append(g.graph[l], u)
	}
	return g
}

func (g *graph) dfs(r, color int) {
	g.colors[r] = color

	stack := list.New()
	stack.PushFront(r)

	for stack.Len() > 0 {
		v := stack.Remove(stack.Front()).(int)
		for _, u := range g.graph[v] {
			if g.colors[u] == nocolor {
				g.colors[u] = color
				stack.PushFront(u)
			}
		}
	}
}

func (g *graph) assignColor() {
	color := 1
	for u := 0; u < len(g.graph); u++ {
		if g.colors[u] == nocolor {
			g.dfs(u, color)
			color++
		}
	}
}

func (g *graph) isLink(s, t int) bool {
	return g.colors[s] == g.colors[t]
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	// construct graph and friendly colors
	g := constructGraph(sc)
	g.assignColor()

	// judge link
	q := nextInt(sc)
	for i := 0; i < q; i++ {
		s := nextInt(sc)
		t := nextInt(sc)

		if g.isLink(s, t) {
			fmt.Println("yes")
		} else {
			fmt.Println("no")
		}
	}
}

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


class LinkedList:
    def __init__(self, n):
        self.n = n
        self.ll = [[] for _ in range(self.n)]

    def link(self, u, v, direction=False):
        self.ll[u].append(v)
        if not direction:
            self.ll[v].append(u)

    def check(self, start, goal):
        states = [0] * self.n
        queue = deque([start])

        while queue:
            u = queue.popleft()
            if states[u]:
                continue
            else:
                states[u] = 1

            for v in self.ll[u]:
                if v == goal:
                    print('yes')
                    return

                if states[v]:
                    continue
                else:
                    queue.append(v)

        else:
            print('no')
            return


if __name__ == '__main__':
    n, m = map(int, input().split())
    ll = LinkedList(n)

    for _ in range(m):
        u, v = map(int, input().split())
        ll.link(u, v)

    q = int(input())
    for _ in range(q):
        u, v = map(int, input().split())
        ll.check(u, v)

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")