Go: package main

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

func getScanner(fp *os.File) *bufio.Scanner {
	scanner := bufio.NewScanner(fp)
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 500001), 500000)
	return scanner
}

func getNextString(scanner *bufio.Scanner) string {
	scanner.Scan()
	return scanner.Text()
}

func getNextInt(scanner *bufio.Scanner) int {
	i, _ := strconv.Atoi(getNextString(scanner))
	return i
}

func main() {
	fp := os.Stdin
	if len(os.Args) > 1 {
		fp, _ = os.Open(os.Args[1])
	}

	scanner := getScanner(fp)
	writer := bufio.NewWriter(os.Stdout)

	n := getNextInt(scanner)
	m := getNextInt(scanner)
	nodes := make([]Node, n)

	for i := 0; i < n; i++ {
		nodes[i].list = make([]int, 0)
	}

	for i := 0; i < m; i++ {
		s := getNextInt(scanner)
		t := getNextInt(scanner)
		nodes[s].list = append(nodes[s].list, t)
		nodes[t].list = append(nodes[t].list, s)
	}

	c := 1
	for i := 0; i < n; i++ {
		if nodes[i].c == 0 {
			traverse(nodes, i, c)
			c++
		}
	}

	q := getNextInt(scanner)

	for i := 0; i < q; i++ {
		s := getNextInt(scanner)
		t := getNextInt(scanner)
		if nodes[s].c == nodes[t].c {
			fmt.Fprintln(writer, "yes")
			continue
		}
		fmt.Fprintln(writer, "no")
	}

	writer.Flush()
}

// Node ...
type Node struct {
	list []int
	c    int
}

func traverse(nodes []Node, r, c int) {
	nodes[r].c = c
	for _, i := range nodes[r].list {
		if nodes[i].c != 0 {
			continue
		}
		traverse(nodes, i, c)
	}
}

Python: n, m = map(int, input().split())
link = [[] for _ in range(n)]
for _ in range(m):
    u, v = map(int, input().split())
    link[u].append(v)
    link[v].append(u)
group = [-1] * n
gid = 0
for i in range(n):
    if group[i] != -1:
        continue
    stack = [i]
    group[i] = gid
    while stack:
        u = stack.pop()
        for v in link[u]:
            if group[v] == -1:
                group[v] = gid
                stack.append(v)
    gid += 1
q = int(input())
for _ in range(q):
    u, v = map(int, input().split())
    print('yes' if group[u] == group[v] else 'no')

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

# dfsで連結成分を求める
r = [0]*n
for i in range(n):
    if r[i] == 0:
        l = [i]
        while len(l) > 0:
            u = l.pop(-1)
            r[u] = i+1
            for v in g[u]:
                if r[v] == 0:
                    l.append(v)

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

Python: 
class UnionFind:
    def __init__(self, n):
        self.n = n
        self.parents = [-1] * n

    def find(self, x):
        if self.parents[x] < 0:
            return x
        else:
            self.parents[x] = self.find(self.parents[x])
            return self.parents[x]

    def union(self, x, y):
        x = self.find(x)
        y = self.find(y)

        if x == y:
            return

        if self.parents[x] > self.parents[y]:
            x, y = y, x

        self.parents[x] += self.parents[y]
        self.parents[y] = x

    def size(self, x):
        return self.parents[self.find(x)]

    def same(self, x, y):
        return self.find(x) == self.find(y)

    def members(self, x):
        root = self.find(x)
        return [i for i in range(self.n) if self.find(i) == root]

    def roots(self):
        return [i for i in range(self.n) if self.parents[i] < 0]

    def group_count(self):
        return len(self.roots())

    def all_group_members(self):
        return {r: self.members(r) for r in self.roots()}

    def __str__(self):
        return "\n".join("{}: {}".format(r, self.members(r)) for r in self.roots())


n,m = map(int,input().split())
tree = UnionFind(n)
for _ in range(m):
    a,b = map(int,input().split())
    tree.union(a,b)

q = int(input())
for i in range(q):
    a,b = map(int,input().split())
    if tree.same(a,b):
        print("yes")
    else:
        print("no")

Python: def dfs(u, color):
    global c
    global g
    s = [u]
    c[u] = color
    while 0 < len(s):
        ch = s.pop()
        for ch in g[ch]:
            u_c = c[ch]
            if u_c is None:
                c[ch] = color
                s.append(ch)

def colorize():
    global g
    global c
    global n
    color = 1
    for i in range(n):
        if c[i] == None:
            dfs(i, color)
            color += 1

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

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

c = [None for i in range(n)]

colorize()

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

Python: # -*- coding: utf-8 -*-

def assignColor():
    C = [-1 for i in range(n)]
    for i in range(n):
        if C[i] == -1:
            C = BFS(i, C)
    return C

#@profile
def BFS(start, C):
    Q = [start]
    C[start] = start

    while len(Q) != 0:
        u = Q.pop(0)
        v = [i for i in G[u] if C[i] == -1] # v := ??£??\???????????????????????¢?´¢??????????????????
        
        for i in v:
            Q.append(i)
            C[i] = C[start]
    
    return C

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

    C = assignColor()
        
    q = int(input())
    
    for i in range(q):
        s, t = list(map(int, input().split()))
        if C[s] == C[t]:
            print("yes")
        else:
            print("no")
            
if __name__ == "__main__":
    n, m = list(map(int, input().split()))
    G = [[] for i in range(n)]

    main()

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

a = [[] for i in range(n)]

for i in range(m):
    com = list(map(int, input().split()))
    a[com[0]].append(com[1])
    a[com[1]].append(com[0])

q = int(input())

from collections import deque
for j in range(q):
    memo = [0 for i in range(n)]
    data = list(map(int, input().split()))
    memo[data[0]] = 1
    queue = deque(data[0])

    try:
        while len(queue):
            b = queue.popleft()
            for k in a[b]:
                if k == data[1]:
                    print("yes")
                    raise Exception
                if memo[k] == 0:
                    memo[k] = 1
                    queue.append(k)
        print("no")
    except Exception:
        pass

Python: n, m = map(int, input().split())
rootList = [-1] * n
 
def getRoot(x):
    if rootList[x] < 0:
        rootList[x] = x
        return x
    return getRoot(rootList[x])
 
 
def setSameRoot(x, y):
    x = getRoot(x)
    y = getRoot(y)
    if x != y:
        rootList[x], rootList[y] = min(x, y), min(x, y)
 
for i in range(m):
    s, t = map(int, input().split())
    setSameRoot(s, t)
q = int(input())
for i in range(q):
    s, t = map(int, input().split())
    print("yes" if getRoot(s) == getRoot(t) else "no")

Python: def dfs(r, c):
    global color
    global g
    s = [r]
    color[r] = c
    while len(s) > 0:
        u = s.pop()
        for u in g[u]:
            v = color[u]
            if v is None:
                color[u] = c
                s.append(u)
                
def assigncolor():
    global g
    global color
    global n
    c = 1
    for i in range(n):
        if color[i] == None:
            dfs(i, c)
            c += 1
            
n, m = list(map(int, input().split()))

g = [[] for i in range(n)]
for i in range(m):
    s, t = list(map(int, input().split()))
    g[s].append(t)
    g[t].append(s)
    
color = [None for i in range(n)]

assigncolor()

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